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Last computer not to use 8-bit bytes
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I am old enough to remember computers that were not byte oriented. E.g. the first that I used was an ICL 4120. It had 24 bit words which were, when necessary, divided into four 6-bit characters. There were operations to support extracting the 6 bit characters from the words. There were no corresponding operations to extract three 8 bit sub-units.
Today, I am unaware of a computer that is not byte oriented.
Do any remain in production? If not which was the last? Two interpretations of last are interesting: the last to be launched and the last to remain on sale (as new).
Update 1: it seems that some non-byte chips are still in production. I will need to think of a way to narrow down the question.
Update 2: On byte oriented, I did not intend to exclude 16, 32, and 64 bit processors but most popular current CPUs still have substantial support for operations involving 8 bit bytes. I was looking for examples where 8 bits is not significant e.g. my old ICL example, 24 bit words, some support for 6 bit sub-units but no support for 8 bit operations. For example, their memory would not be measured in 8 bit bytes.
Update 3: I have been assuming byte as 8 bits. If the term byte is used but it does not represent 8 bits then that would also be interesting.
Update 4: It has been suggested that I use "octet" in place of "byte". This may be more precise but it is rarely used in English (I know that it is common in French). As I said, I would interested in systems which used the term "byte" for other than 8 bits but in contemporary usage, byte is 8 bits so I will stick with it.
Update 5: To narrow down the question and make it more answerable, I'll add the requirement that the system is capable of some form of textual I/O to a user; more than a limited range of fixed messages. So, chips used only inside calculators or controllers are excluded.
memory
asked 23 hours ago
badjohn
533112
 |Â
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up vote
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I am old enough to remember computers that were not byte oriented. E.g. the first that I used was an ICL 4120. It had 24 bit words which were, when necessary, divided into four 6-bit characters. There were operations to support extracting the 6 bit characters from the words. There were no corresponding operations to extract three 8 bit sub-units.
Today, I am unaware of a computer that is not byte oriented.
Do any remain in production? If not which was the last? Two interpretations of last are interesting: the last to be launched and the last to remain on sale (as new).
Update 1: it seems that some non-byte chips are still in production. I will need to think of a way to narrow down the question.
Update 2: On byte oriented, I did not intend to exclude 16, 32, and 64 bit processors but most popular current CPUs still have substantial support for operations involving 8 bit bytes. I was looking for examples where 8 bits is not significant e.g. my old ICL example, 24 bit words, some support for 6 bit sub-units but no support for 8 bit operations. For example, their memory would not be measured in 8 bit bytes.
Update 3: I have been assuming byte as 8 bits. If the term byte is used but it does not represent 8 bits then that would also be interesting.
Update 4: It has been suggested that I use "octet" in place of "byte". This may be more precise but it is rarely used in English (I know that it is common in French). As I said, I would interested in systems which used the term "byte" for other than 8 bits but in contemporary usage, byte is 8 bits so I will stick with it.
Update 5: To narrow down the question and make it more answerable, I'll add the requirement that the system is capable of some form of textual I/O to a user; more than a limited range of fixed messages. So, chips used only inside calculators or controllers are excluded.
memory
asked 23 hours ago
badjohn
533112
3
A lot of modern DSPs (e.g. TI TMS 32000 series) use "bytes" that have 16 bits: processors.wiki.ti.com/index.php/…
– tofro
22 hours ago
2
Many Harvard type CPUs use different size for programm and data memory, so PICs can be had in 12, 14 and 16 bit program word size. If your question is about Von Neumann machines, then we need to seperate between (logic) byte addressing and physical interface - for example modern x86 CPUs have a physical interface of 8 or more bytes wide, while on a locical level they operate bytewise. and so on. There's no real answer to that.
– Raffzahn
22 hours ago
6
"byte" and "character" didn't always mean the same thing on word-addressable computers. For example the CDC 6600, 7600, and the early Cyber series word-addressable machines had 60-bit words divided into 5 12-bit bytes, but characters were 6 bits, with 10 to a word. There were machine code instructions that operated on bytes, but accessing a single character needed a sequence of shift and mask instructions.
– alephzero
22 hours ago
6
4-bit microcontrollers are still sold today so arguably the last computer hasn't been made yet.
– Ken Gober
16 hours ago
3
Note that defining bytes as 8 bits wasn't always the norm. In languages like C++ byte is defined as the smallest addressable unit of at least 8 bits, possibly more...
– PlasmaHH
16 hours ago
 |Â
show 17 more comments
up vote
12
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favorite
up vote
12
down vote
favorite
I am old enough to remember computers that were not byte oriented. E.g. the first that I used was an ICL 4120. It had 24 bit words which were, when necessary, divided into four 6-bit characters. There were operations to support extracting the 6 bit characters from the words. There were no corresponding operations to extract three 8 bit sub-units.
Today, I am unaware of a computer that is not byte oriented.
Do any remain in production? If not which was the last? Two interpretations of last are interesting: the last to be launched and the last to remain on sale (as new).
Update 1: it seems that some non-byte chips are still in production. I will need to think of a way to narrow down the question.
Update 2: On byte oriented, I did not intend to exclude 16, 32, and 64 bit processors but most popular current CPUs still have substantial support for operations involving 8 bit bytes. I was looking for examples where 8 bits is not significant e.g. my old ICL example, 24 bit words, some support for 6 bit sub-units but no support for 8 bit operations. For example, their memory would not be measured in 8 bit bytes.
Update 3: I have been assuming byte as 8 bits. If the term byte is used but it does not represent 8 bits then that would also be interesting.
Update 4: It has been suggested that I use "octet" in place of "byte". This may be more precise but it is rarely used in English (I know that it is common in French). As I said, I would interested in systems which used the term "byte" for other than 8 bits but in contemporary usage, byte is 8 bits so I will stick with it.
Update 5: To narrow down the question and make it more answerable, I'll add the requirement that the system is capable of some form of textual I/O to a user; more than a limited range of fixed messages. So, chips used only inside calculators or controllers are excluded.
memory
asked 23 hours ago
badjohn
533112
I am old enough to remember computers that were not byte oriented. E.g. the first that I used was an ICL 4120. It had 24 bit words which were, when necessary, divided into four 6-bit characters. There were operations to support extracting the 6 bit characters from the words. There were no corresponding operations to extract three 8 bit sub-units.
Today, I am unaware of a computer that is not byte oriented.
Do any remain in production? If not which was the last? Two interpretations of last are interesting: the last to be launched and the last to remain on sale (as new).
Update 1: it seems that some non-byte chips are still in production. I will need to think of a way to narrow down the question.
Update 2: On byte oriented, I did not intend to exclude 16, 32, and 64 bit processors but most popular current CPUs still have substantial support for operations involving 8 bit bytes. I was looking for examples where 8 bits is not significant e.g. my old ICL example, 24 bit words, some support for 6 bit sub-units but no support for 8 bit operations. For example, their memory would not be measured in 8 bit bytes.
Update 3: I have been assuming byte as 8 bits. If the term byte is used but it does not represent 8 bits then that would also be interesting.
Update 4: It has been suggested that I use "octet" in place of "byte". This may be more precise but it is rarely used in English (I know that it is common in French). As I said, I would interested in systems which used the term "byte" for other than 8 bits but in contemporary usage, byte is 8 bits so I will stick with it.
Update 5: To narrow down the question and make it more answerable, I'll add the requirement that the system is capable of some form of textual I/O to a user; more than a limited range of fixed messages. So, chips used only inside calculators or controllers are excluded.
memory
memory
asked 23 hours ago
badjohn
533112
asked 23 hours ago
badjohn
533112
edited 9 mins ago
asked 23 hours ago
badjohn
533112
asked 23 hours ago
badjohn
533112
asked 23 hours ago
badjohn
533112
533112
3
A lot of modern DSPs (e.g. TI TMS 32000 series) use "bytes" that have 16 bits: processors.wiki.ti.com/index.php/…
– tofro
22 hours ago
2
Many Harvard type CPUs use different size for programm and data memory, so PICs can be had in 12, 14 and 16 bit program word size. If your question is about Von Neumann machines, then we need to seperate between (logic) byte addressing and physical interface - for example modern x86 CPUs have a physical interface of 8 or more bytes wide, while on a locical level they operate bytewise. and so on. There's no real answer to that.
– Raffzahn
22 hours ago
6
"byte" and "character" didn't always mean the same thing on word-addressable computers. For example the CDC 6600, 7600, and the early Cyber series word-addressable machines had 60-bit words divided into 5 12-bit bytes, but characters were 6 bits, with 10 to a word. There were machine code instructions that operated on bytes, but accessing a single character needed a sequence of shift and mask instructions.
– alephzero
22 hours ago
6
4-bit microcontrollers are still sold today so arguably the last computer hasn't been made yet.
– Ken Gober
16 hours ago
3
Note that defining bytes as 8 bits wasn't always the norm. In languages like C++ byte is defined as the smallest addressable unit of at least 8 bits, possibly more...
– PlasmaHH
16 hours ago
 |Â
show 17 more comments
3
A lot of modern DSPs (e.g. TI TMS 32000 series) use "bytes" that have 16 bits: processors.wiki.ti.com/index.php/…
– tofro
22 hours ago
2
Many Harvard type CPUs use different size for programm and data memory, so PICs can be had in 12, 14 and 16 bit program word size. If your question is about Von Neumann machines, then we need to seperate between (logic) byte addressing and physical interface - for example modern x86 CPUs have a physical interface of 8 or more bytes wide, while on a locical level they operate bytewise. and so on. There's no real answer to that.
– Raffzahn
22 hours ago
6
"byte" and "character" didn't always mean the same thing on word-addressable computers. For example the CDC 6600, 7600, and the early Cyber series word-addressable machines had 60-bit words divided into 5 12-bit bytes, but characters were 6 bits, with 10 to a word. There were machine code instructions that operated on bytes, but accessing a single character needed a sequence of shift and mask instructions.
– alephzero
22 hours ago
6
4-bit microcontrollers are still sold today so arguably the last computer hasn't been made yet.
– Ken Gober
16 hours ago
3
Note that defining bytes as 8 bits wasn't always the norm. In languages like C++ byte is defined as the smallest addressable unit of at least 8 bits, possibly more...
– PlasmaHH
16 hours ago
3
3
A lot of modern DSPs (e.g. TI TMS 32000 series) use "bytes" that have 16 bits: processors.wiki.ti.com/index.php/…
– tofro
22 hours ago
A lot of modern DSPs (e.g. TI TMS 32000 series) use "bytes" that have 16 bits: processors.wiki.ti.com/index.php/…
– tofro
22 hours ago
2
2
Many Harvard type CPUs use different size for programm and data memory, so PICs can be had in 12, 14 and 16 bit program word size. If your question is about Von Neumann machines, then we need to seperate between (logic) byte addressing and physical interface - for example modern x86 CPUs have a physical interface of 8 or more bytes wide, while on a locical level they operate bytewise. and so on. There's no real answer to that.
– Raffzahn
22 hours ago
Many Harvard type CPUs use different size for programm and data memory, so PICs can be had in 12, 14 and 16 bit program word size. If your question is about Von Neumann machines, then we need to seperate between (logic) byte addressing and physical interface - for example modern x86 CPUs have a physical interface of 8 or more bytes wide, while on a locical level they operate bytewise. and so on. There's no real answer to that.
– Raffzahn
22 hours ago
6
6
"byte" and "character" didn't always mean the same thing on word-addressable computers. For example the CDC 6600, 7600, and the early Cyber series word-addressable machines had 60-bit words divided into 5 12-bit bytes, but characters were 6 bits, with 10 to a word. There were machine code instructions that operated on bytes, but accessing a single character needed a sequence of shift and mask instructions.
– alephzero
22 hours ago
"byte" and "character" didn't always mean the same thing on word-addressable computers. For example the CDC 6600, 7600, and the early Cyber series word-addressable machines had 60-bit words divided into 5 12-bit bytes, but characters were 6 bits, with 10 to a word. There were machine code instructions that operated on bytes, but accessing a single character needed a sequence of shift and mask instructions.
– alephzero
22 hours ago
6
6
4-bit microcontrollers are still sold today so arguably the last computer hasn't been made yet.
– Ken Gober
16 hours ago
4-bit microcontrollers are still sold today so arguably the last computer hasn't been made yet.
– Ken Gober
16 hours ago
3
3
Note that defining bytes as 8 bits wasn't always the norm. In languages like C++ byte is defined as the smallest addressable unit of at least 8 bits, possibly more...
– PlasmaHH
16 hours ago
Note that defining bytes as 8 bits wasn't always the norm. In languages like C++ byte is defined as the smallest addressable unit of at least 8 bits, possibly more...
– PlasmaHH
16 hours ago
 |Â
show 17 more comments
6 Answers
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In the early 1990's CDC sold a line of Cyber 180 mainframes. These machines were descendants of the CDC 6600 and supported that machine's 60-bit word size and 6-bit characters. Notably, one of the innovations of the 180 over the 170 is that the 180 added support for 64-bit words and 8-bit characters, and could run software written for both modes simultaneously. So this is probably towards the tail end of sub-8-bit character oriented computing, at least at commercial data processing scale.
At the other end of the spectrum, HP calculators used a series of fully custom four bit CPUs that shipped as late as the early 2000's. These started out as custom multi-chip devices and evolved into what we'd now consider a system on a chip, with some mixed analog and digital logic on the same die. CPU characteristics are what you'd expect from a custom chip for this purpose: highly optimized for calculator operations. This means 4-bit data paths and and ALU that has both BCD and Binary modes. There were also 64-bit wide registers (16 digits) for numbers and 20-bit wide registers for the 1M-nybble address space. Also, there were a number of CPU operations for specific fields of the larger registers (mantissa, exponent, etc.) Around 2002-3, HP switched to using a commodity ARM part running an emulator of the older custom CPU. (And I believe that was their final calculator architecture.)
answered 17 hours ago
mschaef
1,981514
Thanks. This is the type of answer that I was hoping for.
– badjohn
19 mins ago
add a comment |Â
up vote
13
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Such a question is a bit difficult, or rather impossible, to answer. While it is true that most mainstream computers today use units of 8 bits for bytes and and, at least Latin, characters, there always have been and still are exceptions. So, the answer to your "the last one" question probably is "there is none".
There are a number of widespread embedded MCUs with Harvard architecture that use 12-, 14- (PIC) or 16-bit wide (AVR) program memory and disallow 8-bit access to this memory. A "byte" in program memory for those MCUs thus has the above width.
The same thing applies for a lot of DSPs - They have byte widths of typically between 16 and 24 bits and very rarely allow (8-bit-)byte extraction from this memory. Typical examples would be the TMS 32000 (TI) or DSP56000 (Motorola/Freescale/NXP)
It is disputable whether systems based on either of these MCUs/DSPs should be considered "computers", but in my book they have to.
In a less strict sense, even relatively modern CPUs like MIPS could be considered to use, in this specific case, 32-bit "bytes". While the MIPS architecture has the concept of "8-bit bytes" in internal registers, MIPS CPUs technically cannot do less than 32-bit data transfers from and to memory. A similar restriction applies to the address registers in the Motorola 68k, and even your trusty PC's FPU will not work with anything that's 8-bit only.
What seems to have evolved as a kind of standard, though, is that register and data bus width on most of today's CPUs typically is a multiple of eight.
answered 20 hours ago
tofro
12.8k32673
2
@UncleBod That is not what I meant. What you're referring to is the data bus width (and the 68020 had that configurable, BTW), but you can still load an 8-bit byte into any data register on any 68k CPU. But not into an address register, as these are limited to 16 bit transfers.
– tofro
19 hours ago
1
PIC is definitely uses 8-bit bytes as data, but not as program memory. It does allow storing 8-bit data in its program memory, while not as straighforward (specifically, 14-bit-program-word-sized PICs store single 8-bit byte per program word). AVR, while having 16-bit program bus and 16- or 32-bit instructions, is still able to read its own program memory as bytes (thus, it stores 2 bytes per single word of program memory).
– lvd
18 hours ago
1
@rexkogitans No, it's not. There is no such thing as a "common definition of a byte" - It's defined in most places as ">= 8 bits". It just happens to be 8 bits most often.
– tofro
16 hours ago
5
If one uses the phrase "computer" to refer to "a general-purpose computing device intended to run programs supplied by the user" [as distinct from e.g. a DSP or embedded microcontroller], and uses the term "byte-oriented" to refer to the ability to write individual octets of storage without interfering--even temporarily--with adjacent octets, I think the question would have a definite answer, which I would guess would be the DEC Alpha series whose poor performance in the marketplace was IMHO likely a consequence of the lack of byte-addressable storage.
– supercat
16 hours ago
2
@supercat +1 for using the word "octet" in place of "byte". (An octet is always 8 bits; a byte is most commonly 8 bits but not always.)
– traal
14 hours ago
 |Â
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Unisys continued shipping 36-bit systems far more recently than 1997. The last new 36-bit Dorado - the 800 series -- was released in 2011, and superseded - per my recollection - by the Xeon-based, emulation-oriented 8300 series in 2015. (Xeon emulating the Dorado ISA had made up a progressively larger part of the Dorado product line since the late 1990s, but Unisys CPUs persisted at the high end. A similar story happened with Libra, Unisys's name for the Burroughs Large Systems 48-bit a architecture.)
Groupe Bull released the last of their 36-bit line in 2004, the DPS-9000/TA300; it was subsequently superseded by Itanium systems running an emulator called V9000.
answered 15 hours ago
Lexi
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Together with @mschaef's answer, this is what I was hoping for.
– badjohn
18 mins ago
add a comment |Â
up vote
7
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Univac 36-bit
The Univac 1100/2200 series used a 36-bit word. Many models had functions to work with a word as 4 9-bit "bytes" - using the term byte but fitting your definition of a non-byte computer based on not using 8-bit bytes. I had a few courses on an 1100/80 at the University of Maryland in the early 80s.
The 2200 series appears to have carried on the 36-bit architecture, which in theory means up to at least 1997 according to the Wikipedia article. But the ClearPath series, while compatible with the 1100/2200, also included Xeon which would, by definition, mean it included plenty of 8-bit byte oriented instructions.
answered 18 hours ago
manassehkatz
1,361111
Wikipedia claims that, historically, a byte wasn't necessarily eight bits.
– David Richerby
16 hours ago
@DavidRicherby Correct. But OP said things like "I was looking for examples where 8 bits is not significant" so I think a non-multiple-of-8-bit-word system counts, even if the manufacturer uses the word "byte" as long as they don't use "byte" to refer to "8 bits".
– manassehkatz
16 hours ago
Thanks for the example of a byte that was not 8 bits.
– badjohn
17 mins ago
add a comment |Â
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3
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The PDP-8 and its derivatives were 12-bit machines using (at least sometimes) 6-bit characters. While the last actual PDP-8 ceased production in 1980, by that time other systems existed that used microprocessors based on the architecture, and they continued to be produced for many years (the DECmate word processing system, for example, was produced until 1990). Also, as many PDP-8s found their way into industrial control systems and other applications that change infrequently, they have been very long-lived. It's not clear to me whether any are still in actual production use today, but certainly they were in use relatively recently, and this site suggests they were definitely in use as recently as 2000.
answered 14 hours ago
Jules
7,97312142
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up vote
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The Intel 4040 processor may well have been the last commonly used sub-8bit processor. Intel produced this series 1974 and 1981. It had a 4-bit architecture (i.e. register size) and generally used Binary Coded Decimal (BCD) arithmetic and I/O. 
(Diagram from Wikipedia)
As to last computer in active use, who knows? There are definitely working examples of several of these architectures in places like https://livingcomputers.org
P.S. Other 4-bit processors are still available for purchase today, e.g. Renesas 4508 group.
answered 12 hours ago
Burt_Harris
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Thanks. I didn't ask for last in active use as I realised that it would impossible to answer. I had hoped that the last to be launched or sold would be possible.
– badjohn
15 mins ago
add a comment |Â
6 Answers
6
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6 Answers
6
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
13
down vote
In the early 1990's CDC sold a line of Cyber 180 mainframes. These machines were descendants of the CDC 6600 and supported that machine's 60-bit word size and 6-bit characters. Notably, one of the innovations of the 180 over the 170 is that the 180 added support for 64-bit words and 8-bit characters, and could run software written for both modes simultaneously. So this is probably towards the tail end of sub-8-bit character oriented computing, at least at commercial data processing scale.
At the other end of the spectrum, HP calculators used a series of fully custom four bit CPUs that shipped as late as the early 2000's. These started out as custom multi-chip devices and evolved into what we'd now consider a system on a chip, with some mixed analog and digital logic on the same die. CPU characteristics are what you'd expect from a custom chip for this purpose: highly optimized for calculator operations. This means 4-bit data paths and and ALU that has both BCD and Binary modes. There were also 64-bit wide registers (16 digits) for numbers and 20-bit wide registers for the 1M-nybble address space. Also, there were a number of CPU operations for specific fields of the larger registers (mantissa, exponent, etc.) Around 2002-3, HP switched to using a commodity ARM part running an emulator of the older custom CPU. (And I believe that was their final calculator architecture.)
answered 17 hours ago
mschaef
1,981514
Thanks. This is the type of answer that I was hoping for.
– badjohn
19 mins ago
add a comment |Â
up vote
13
down vote
In the early 1990's CDC sold a line of Cyber 180 mainframes. These machines were descendants of the CDC 6600 and supported that machine's 60-bit word size and 6-bit characters. Notably, one of the innovations of the 180 over the 170 is that the 180 added support for 64-bit words and 8-bit characters, and could run software written for both modes simultaneously. So this is probably towards the tail end of sub-8-bit character oriented computing, at least at commercial data processing scale.
At the other end of the spectrum, HP calculators used a series of fully custom four bit CPUs that shipped as late as the early 2000's. These started out as custom multi-chip devices and evolved into what we'd now consider a system on a chip, with some mixed analog and digital logic on the same die. CPU characteristics are what you'd expect from a custom chip for this purpose: highly optimized for calculator operations. This means 4-bit data paths and and ALU that has both BCD and Binary modes. There were also 64-bit wide registers (16 digits) for numbers and 20-bit wide registers for the 1M-nybble address space. Also, there were a number of CPU operations for specific fields of the larger registers (mantissa, exponent, etc.) Around 2002-3, HP switched to using a commodity ARM part running an emulator of the older custom CPU. (And I believe that was their final calculator architecture.)
answered 17 hours ago
mschaef
1,981514
Thanks. This is the type of answer that I was hoping for.
– badjohn
19 mins ago
add a comment |Â
up vote
13
down vote
up vote
13
down vote
In the early 1990's CDC sold a line of Cyber 180 mainframes. These machines were descendants of the CDC 6600 and supported that machine's 60-bit word size and 6-bit characters. Notably, one of the innovations of the 180 over the 170 is that the 180 added support for 64-bit words and 8-bit characters, and could run software written for both modes simultaneously. So this is probably towards the tail end of sub-8-bit character oriented computing, at least at commercial data processing scale.
At the other end of the spectrum, HP calculators used a series of fully custom four bit CPUs that shipped as late as the early 2000's. These started out as custom multi-chip devices and evolved into what we'd now consider a system on a chip, with some mixed analog and digital logic on the same die. CPU characteristics are what you'd expect from a custom chip for this purpose: highly optimized for calculator operations. This means 4-bit data paths and and ALU that has both BCD and Binary modes. There were also 64-bit wide registers (16 digits) for numbers and 20-bit wide registers for the 1M-nybble address space. Also, there were a number of CPU operations for specific fields of the larger registers (mantissa, exponent, etc.) Around 2002-3, HP switched to using a commodity ARM part running an emulator of the older custom CPU. (And I believe that was their final calculator architecture.)
answered 17 hours ago
mschaef
1,981514
In the early 1990's CDC sold a line of Cyber 180 mainframes. These machines were descendants of the CDC 6600 and supported that machine's 60-bit word size and 6-bit characters. Notably, one of the innovations of the 180 over the 170 is that the 180 added support for 64-bit words and 8-bit characters, and could run software written for both modes simultaneously. So this is probably towards the tail end of sub-8-bit character oriented computing, at least at commercial data processing scale.
At the other end of the spectrum, HP calculators used a series of fully custom four bit CPUs that shipped as late as the early 2000's. These started out as custom multi-chip devices and evolved into what we'd now consider a system on a chip, with some mixed analog and digital logic on the same die. CPU characteristics are what you'd expect from a custom chip for this purpose: highly optimized for calculator operations. This means 4-bit data paths and and ALU that has both BCD and Binary modes. There were also 64-bit wide registers (16 digits) for numbers and 20-bit wide registers for the 1M-nybble address space. Also, there were a number of CPU operations for specific fields of the larger registers (mantissa, exponent, etc.) Around 2002-3, HP switched to using a commodity ARM part running an emulator of the older custom CPU. (And I believe that was their final calculator architecture.)
answered 17 hours ago
mschaef
1,981514
edited 11 hours ago
answered 17 hours ago
mschaef
1,981514
answered 17 hours ago
mschaef
1,981514
answered 17 hours ago
mschaef
1,981514
1,981514
Thanks. This is the type of answer that I was hoping for.
– badjohn
19 mins ago
add a comment |Â
Thanks. This is the type of answer that I was hoping for.
– badjohn
19 mins ago
Thanks. This is the type of answer that I was hoping for.
– badjohn
19 mins ago
Thanks. This is the type of answer that I was hoping for.
– badjohn
19 mins ago
add a comment |Â
up vote
13
down vote
Such a question is a bit difficult, or rather impossible, to answer. While it is true that most mainstream computers today use units of 8 bits for bytes and and, at least Latin, characters, there always have been and still are exceptions. So, the answer to your "the last one" question probably is "there is none".
There are a number of widespread embedded MCUs with Harvard architecture that use 12-, 14- (PIC) or 16-bit wide (AVR) program memory and disallow 8-bit access to this memory. A "byte" in program memory for those MCUs thus has the above width.
The same thing applies for a lot of DSPs - They have byte widths of typically between 16 and 24 bits and very rarely allow (8-bit-)byte extraction from this memory. Typical examples would be the TMS 32000 (TI) or DSP56000 (Motorola/Freescale/NXP)
It is disputable whether systems based on either of these MCUs/DSPs should be considered "computers", but in my book they have to.
In a less strict sense, even relatively modern CPUs like MIPS could be considered to use, in this specific case, 32-bit "bytes". While the MIPS architecture has the concept of "8-bit bytes" in internal registers, MIPS CPUs technically cannot do less than 32-bit data transfers from and to memory. A similar restriction applies to the address registers in the Motorola 68k, and even your trusty PC's FPU will not work with anything that's 8-bit only.
What seems to have evolved as a kind of standard, though, is that register and data bus width on most of today's CPUs typically is a multiple of eight.
answered 20 hours ago
tofro
12.8k32673
2
@UncleBod That is not what I meant. What you're referring to is the data bus width (and the 68020 had that configurable, BTW), but you can still load an 8-bit byte into any data register on any 68k CPU. But not into an address register, as these are limited to 16 bit transfers.
– tofro
19 hours ago
1
PIC is definitely uses 8-bit bytes as data, but not as program memory. It does allow storing 8-bit data in its program memory, while not as straighforward (specifically, 14-bit-program-word-sized PICs store single 8-bit byte per program word). AVR, while having 16-bit program bus and 16- or 32-bit instructions, is still able to read its own program memory as bytes (thus, it stores 2 bytes per single word of program memory).
– lvd
18 hours ago
1
@rexkogitans No, it's not. There is no such thing as a "common definition of a byte" - It's defined in most places as ">= 8 bits". It just happens to be 8 bits most often.
– tofro
16 hours ago
5
If one uses the phrase "computer" to refer to "a general-purpose computing device intended to run programs supplied by the user" [as distinct from e.g. a DSP or embedded microcontroller], and uses the term "byte-oriented" to refer to the ability to write individual octets of storage without interfering--even temporarily--with adjacent octets, I think the question would have a definite answer, which I would guess would be the DEC Alpha series whose poor performance in the marketplace was IMHO likely a consequence of the lack of byte-addressable storage.
– supercat
16 hours ago
2
@supercat +1 for using the word "octet" in place of "byte". (An octet is always 8 bits; a byte is most commonly 8 bits but not always.)
– traal
14 hours ago
 |Â
show 9 more comments
up vote
13
down vote
Such a question is a bit difficult, or rather impossible, to answer. While it is true that most mainstream computers today use units of 8 bits for bytes and and, at least Latin, characters, there always have been and still are exceptions. So, the answer to your "the last one" question probably is "there is none".
There are a number of widespread embedded MCUs with Harvard architecture that use 12-, 14- (PIC) or 16-bit wide (AVR) program memory and disallow 8-bit access to this memory. A "byte" in program memory for those MCUs thus has the above width.
The same thing applies for a lot of DSPs - They have byte widths of typically between 16 and 24 bits and very rarely allow (8-bit-)byte extraction from this memory. Typical examples would be the TMS 32000 (TI) or DSP56000 (Motorola/Freescale/NXP)
It is disputable whether systems based on either of these MCUs/DSPs should be considered "computers", but in my book they have to.
In a less strict sense, even relatively modern CPUs like MIPS could be considered to use, in this specific case, 32-bit "bytes". While the MIPS architecture has the concept of "8-bit bytes" in internal registers, MIPS CPUs technically cannot do less than 32-bit data transfers from and to memory. A similar restriction applies to the address registers in the Motorola 68k, and even your trusty PC's FPU will not work with anything that's 8-bit only.
What seems to have evolved as a kind of standard, though, is that register and data bus width on most of today's CPUs typically is a multiple of eight.
answered 20 hours ago
tofro
12.8k32673
2
@UncleBod That is not what I meant. What you're referring to is the data bus width (and the 68020 had that configurable, BTW), but you can still load an 8-bit byte into any data register on any 68k CPU. But not into an address register, as these are limited to 16 bit transfers.
– tofro
19 hours ago
1
PIC is definitely uses 8-bit bytes as data, but not as program memory. It does allow storing 8-bit data in its program memory, while not as straighforward (specifically, 14-bit-program-word-sized PICs store single 8-bit byte per program word). AVR, while having 16-bit program bus and 16- or 32-bit instructions, is still able to read its own program memory as bytes (thus, it stores 2 bytes per single word of program memory).
– lvd
18 hours ago
1
@rexkogitans No, it's not. There is no such thing as a "common definition of a byte" - It's defined in most places as ">= 8 bits". It just happens to be 8 bits most often.
– tofro
16 hours ago
5
If one uses the phrase "computer" to refer to "a general-purpose computing device intended to run programs supplied by the user" [as distinct from e.g. a DSP or embedded microcontroller], and uses the term "byte-oriented" to refer to the ability to write individual octets of storage without interfering--even temporarily--with adjacent octets, I think the question would have a definite answer, which I would guess would be the DEC Alpha series whose poor performance in the marketplace was IMHO likely a consequence of the lack of byte-addressable storage.
– supercat
16 hours ago
2
@supercat +1 for using the word "octet" in place of "byte". (An octet is always 8 bits; a byte is most commonly 8 bits but not always.)
– traal
14 hours ago
 |Â
show 9 more comments
up vote
13
down vote
up vote
13
down vote
Such a question is a bit difficult, or rather impossible, to answer. While it is true that most mainstream computers today use units of 8 bits for bytes and and, at least Latin, characters, there always have been and still are exceptions. So, the answer to your "the last one" question probably is "there is none".
There are a number of widespread embedded MCUs with Harvard architecture that use 12-, 14- (PIC) or 16-bit wide (AVR) program memory and disallow 8-bit access to this memory. A "byte" in program memory for those MCUs thus has the above width.
The same thing applies for a lot of DSPs - They have byte widths of typically between 16 and 24 bits and very rarely allow (8-bit-)byte extraction from this memory. Typical examples would be the TMS 32000 (TI) or DSP56000 (Motorola/Freescale/NXP)
It is disputable whether systems based on either of these MCUs/DSPs should be considered "computers", but in my book they have to.
In a less strict sense, even relatively modern CPUs like MIPS could be considered to use, in this specific case, 32-bit "bytes". While the MIPS architecture has the concept of "8-bit bytes" in internal registers, MIPS CPUs technically cannot do less than 32-bit data transfers from and to memory. A similar restriction applies to the address registers in the Motorola 68k, and even your trusty PC's FPU will not work with anything that's 8-bit only.
What seems to have evolved as a kind of standard, though, is that register and data bus width on most of today's CPUs typically is a multiple of eight.
answered 20 hours ago
tofro
12.8k32673
Such a question is a bit difficult, or rather impossible, to answer. While it is true that most mainstream computers today use units of 8 bits for bytes and and, at least Latin, characters, there always have been and still are exceptions. So, the answer to your "the last one" question probably is "there is none".
There are a number of widespread embedded MCUs with Harvard architecture that use 12-, 14- (PIC) or 16-bit wide (AVR) program memory and disallow 8-bit access to this memory. A "byte" in program memory for those MCUs thus has the above width.
The same thing applies for a lot of DSPs - They have byte widths of typically between 16 and 24 bits and very rarely allow (8-bit-)byte extraction from this memory. Typical examples would be the TMS 32000 (TI) or DSP56000 (Motorola/Freescale/NXP)
It is disputable whether systems based on either of these MCUs/DSPs should be considered "computers", but in my book they have to.
In a less strict sense, even relatively modern CPUs like MIPS could be considered to use, in this specific case, 32-bit "bytes". While the MIPS architecture has the concept of "8-bit bytes" in internal registers, MIPS CPUs technically cannot do less than 32-bit data transfers from and to memory. A similar restriction applies to the address registers in the Motorola 68k, and even your trusty PC's FPU will not work with anything that's 8-bit only.
What seems to have evolved as a kind of standard, though, is that register and data bus width on most of today's CPUs typically is a multiple of eight.
answered 20 hours ago
tofro
12.8k32673
edited 17 mins ago
answered 20 hours ago
tofro
12.8k32673
answered 20 hours ago
tofro
12.8k32673
answered 20 hours ago
tofro
12.8k32673
12.8k32673
2
@UncleBod That is not what I meant. What you're referring to is the data bus width (and the 68020 had that configurable, BTW), but you can still load an 8-bit byte into any data register on any 68k CPU. But not into an address register, as these are limited to 16 bit transfers.
– tofro
19 hours ago
1
PIC is definitely uses 8-bit bytes as data, but not as program memory. It does allow storing 8-bit data in its program memory, while not as straighforward (specifically, 14-bit-program-word-sized PICs store single 8-bit byte per program word). AVR, while having 16-bit program bus and 16- or 32-bit instructions, is still able to read its own program memory as bytes (thus, it stores 2 bytes per single word of program memory).
– lvd
18 hours ago
1
@rexkogitans No, it's not. There is no such thing as a "common definition of a byte" - It's defined in most places as ">= 8 bits". It just happens to be 8 bits most often.
– tofro
16 hours ago
5
If one uses the phrase "computer" to refer to "a general-purpose computing device intended to run programs supplied by the user" [as distinct from e.g. a DSP or embedded microcontroller], and uses the term "byte-oriented" to refer to the ability to write individual octets of storage without interfering--even temporarily--with adjacent octets, I think the question would have a definite answer, which I would guess would be the DEC Alpha series whose poor performance in the marketplace was IMHO likely a consequence of the lack of byte-addressable storage.
– supercat
16 hours ago
2
@supercat +1 for using the word "octet" in place of "byte". (An octet is always 8 bits; a byte is most commonly 8 bits but not always.)
– traal
14 hours ago
 |Â
show 9 more comments
2
@UncleBod That is not what I meant. What you're referring to is the data bus width (and the 68020 had that configurable, BTW), but you can still load an 8-bit byte into any data register on any 68k CPU. But not into an address register, as these are limited to 16 bit transfers.
– tofro
19 hours ago
1
PIC is definitely uses 8-bit bytes as data, but not as program memory. It does allow storing 8-bit data in its program memory, while not as straighforward (specifically, 14-bit-program-word-sized PICs store single 8-bit byte per program word). AVR, while having 16-bit program bus and 16- or 32-bit instructions, is still able to read its own program memory as bytes (thus, it stores 2 bytes per single word of program memory).
– lvd
18 hours ago
1
@rexkogitans No, it's not. There is no such thing as a "common definition of a byte" - It's defined in most places as ">= 8 bits". It just happens to be 8 bits most often.
– tofro
16 hours ago
5
If one uses the phrase "computer" to refer to "a general-purpose computing device intended to run programs supplied by the user" [as distinct from e.g. a DSP or embedded microcontroller], and uses the term "byte-oriented" to refer to the ability to write individual octets of storage without interfering--even temporarily--with adjacent octets, I think the question would have a definite answer, which I would guess would be the DEC Alpha series whose poor performance in the marketplace was IMHO likely a consequence of the lack of byte-addressable storage.
– supercat
16 hours ago
2
@supercat +1 for using the word "octet" in place of "byte". (An octet is always 8 bits; a byte is most commonly 8 bits but not always.)
– traal
14 hours ago
2
2
@UncleBod That is not what I meant. What you're referring to is the data bus width (and the 68020 had that configurable, BTW), but you can still load an 8-bit byte into any data register on any 68k CPU. But not into an address register, as these are limited to 16 bit transfers.
– tofro
19 hours ago
@UncleBod That is not what I meant. What you're referring to is the data bus width (and the 68020 had that configurable, BTW), but you can still load an 8-bit byte into any data register on any 68k CPU. But not into an address register, as these are limited to 16 bit transfers.
– tofro
19 hours ago
1
1
PIC is definitely uses 8-bit bytes as data, but not as program memory. It does allow storing 8-bit data in its program memory, while not as straighforward (specifically, 14-bit-program-word-sized PICs store single 8-bit byte per program word). AVR, while having 16-bit program bus and 16- or 32-bit instructions, is still able to read its own program memory as bytes (thus, it stores 2 bytes per single word of program memory).
– lvd
18 hours ago
PIC is definitely uses 8-bit bytes as data, but not as program memory. It does allow storing 8-bit data in its program memory, while not as straighforward (specifically, 14-bit-program-word-sized PICs store single 8-bit byte per program word). AVR, while having 16-bit program bus and 16- or 32-bit instructions, is still able to read its own program memory as bytes (thus, it stores 2 bytes per single word of program memory).
– lvd
18 hours ago
1
1
@rexkogitans No, it's not. There is no such thing as a "common definition of a byte" - It's defined in most places as ">= 8 bits". It just happens to be 8 bits most often.
– tofro
16 hours ago
@rexkogitans No, it's not. There is no such thing as a "common definition of a byte" - It's defined in most places as ">= 8 bits". It just happens to be 8 bits most often.
– tofro
16 hours ago
5
5
If one uses the phrase "computer" to refer to "a general-purpose computing device intended to run programs supplied by the user" [as distinct from e.g. a DSP or embedded microcontroller], and uses the term "byte-oriented" to refer to the ability to write individual octets of storage without interfering--even temporarily--with adjacent octets, I think the question would have a definite answer, which I would guess would be the DEC Alpha series whose poor performance in the marketplace was IMHO likely a consequence of the lack of byte-addressable storage.
– supercat
16 hours ago
If one uses the phrase "computer" to refer to "a general-purpose computing device intended to run programs supplied by the user" [as distinct from e.g. a DSP or embedded microcontroller], and uses the term "byte-oriented" to refer to the ability to write individual octets of storage without interfering--even temporarily--with adjacent octets, I think the question would have a definite answer, which I would guess would be the DEC Alpha series whose poor performance in the marketplace was IMHO likely a consequence of the lack of byte-addressable storage.
– supercat
16 hours ago
2
2
@supercat +1 for using the word "octet" in place of "byte". (An octet is always 8 bits; a byte is most commonly 8 bits but not always.)
– traal
14 hours ago
@supercat +1 for using the word "octet" in place of "byte". (An octet is always 8 bits; a byte is most commonly 8 bits but not always.)
– traal
14 hours ago
 |Â
show 9 more comments
up vote
8
down vote
Unisys continued shipping 36-bit systems far more recently than 1997. The last new 36-bit Dorado - the 800 series -- was released in 2011, and superseded - per my recollection - by the Xeon-based, emulation-oriented 8300 series in 2015. (Xeon emulating the Dorado ISA had made up a progressively larger part of the Dorado product line since the late 1990s, but Unisys CPUs persisted at the high end. A similar story happened with Libra, Unisys's name for the Burroughs Large Systems 48-bit a architecture.)
Groupe Bull released the last of their 36-bit line in 2004, the DPS-9000/TA300; it was subsequently superseded by Itanium systems running an emulator called V9000.
answered 15 hours ago
Lexi
811
New contributor
Lexi is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Together with @mschaef's answer, this is what I was hoping for.
– badjohn
18 mins ago
add a comment |Â
up vote
8
down vote
Unisys continued shipping 36-bit systems far more recently than 1997. The last new 36-bit Dorado - the 800 series -- was released in 2011, and superseded - per my recollection - by the Xeon-based, emulation-oriented 8300 series in 2015. (Xeon emulating the Dorado ISA had made up a progressively larger part of the Dorado product line since the late 1990s, but Unisys CPUs persisted at the high end. A similar story happened with Libra, Unisys's name for the Burroughs Large Systems 48-bit a architecture.)
Groupe Bull released the last of their 36-bit line in 2004, the DPS-9000/TA300; it was subsequently superseded by Itanium systems running an emulator called V9000.
answered 15 hours ago
Lexi
811
New contributor
Lexi is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Together with @mschaef's answer, this is what I was hoping for.
– badjohn
18 mins ago
add a comment |Â
up vote
8
down vote
up vote
8
down vote
Unisys continued shipping 36-bit systems far more recently than 1997. The last new 36-bit Dorado - the 800 series -- was released in 2011, and superseded - per my recollection - by the Xeon-based, emulation-oriented 8300 series in 2015. (Xeon emulating the Dorado ISA had made up a progressively larger part of the Dorado product line since the late 1990s, but Unisys CPUs persisted at the high end. A similar story happened with Libra, Unisys's name for the Burroughs Large Systems 48-bit a architecture.)
Groupe Bull released the last of their 36-bit line in 2004, the DPS-9000/TA300; it was subsequently superseded by Itanium systems running an emulator called V9000.
answered 15 hours ago
Lexi
811
New contributor
Lexi is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Unisys continued shipping 36-bit systems far more recently than 1997. The last new 36-bit Dorado - the 800 series -- was released in 2011, and superseded - per my recollection - by the Xeon-based, emulation-oriented 8300 series in 2015. (Xeon emulating the Dorado ISA had made up a progressively larger part of the Dorado product line since the late 1990s, but Unisys CPUs persisted at the high end. A similar story happened with Libra, Unisys's name for the Burroughs Large Systems 48-bit a architecture.)
Groupe Bull released the last of their 36-bit line in 2004, the DPS-9000/TA300; it was subsequently superseded by Itanium systems running an emulator called V9000.
answered 15 hours ago
Lexi
811
New contributor
Lexi is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
answered 15 hours ago
Lexi
811
New contributor
Lexi is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
answered 15 hours ago
Lexi
811
answered 15 hours ago
Lexi
811
811
New contributor
Lexi is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
Lexi is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Lexi is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Together with @mschaef's answer, this is what I was hoping for.
– badjohn
18 mins ago
add a comment |Â
Together with @mschaef's answer, this is what I was hoping for.
– badjohn
18 mins ago
Together with @mschaef's answer, this is what I was hoping for.
– badjohn
18 mins ago
Together with @mschaef's answer, this is what I was hoping for.
– badjohn
18 mins ago
add a comment |Â
up vote
7
down vote
Univac 36-bit
The Univac 1100/2200 series used a 36-bit word. Many models had functions to work with a word as 4 9-bit "bytes" - using the term byte but fitting your definition of a non-byte computer based on not using 8-bit bytes. I had a few courses on an 1100/80 at the University of Maryland in the early 80s.
The 2200 series appears to have carried on the 36-bit architecture, which in theory means up to at least 1997 according to the Wikipedia article. But the ClearPath series, while compatible with the 1100/2200, also included Xeon which would, by definition, mean it included plenty of 8-bit byte oriented instructions.
answered 18 hours ago
manassehkatz
1,361111
Wikipedia claims that, historically, a byte wasn't necessarily eight bits.
– David Richerby
16 hours ago
@DavidRicherby Correct. But OP said things like "I was looking for examples where 8 bits is not significant" so I think a non-multiple-of-8-bit-word system counts, even if the manufacturer uses the word "byte" as long as they don't use "byte" to refer to "8 bits".
– manassehkatz
16 hours ago
Thanks for the example of a byte that was not 8 bits.
– badjohn
17 mins ago
add a comment |Â
up vote
7
down vote
Univac 36-bit
The Univac 1100/2200 series used a 36-bit word. Many models had functions to work with a word as 4 9-bit "bytes" - using the term byte but fitting your definition of a non-byte computer based on not using 8-bit bytes. I had a few courses on an 1100/80 at the University of Maryland in the early 80s.
The 2200 series appears to have carried on the 36-bit architecture, which in theory means up to at least 1997 according to the Wikipedia article. But the ClearPath series, while compatible with the 1100/2200, also included Xeon which would, by definition, mean it included plenty of 8-bit byte oriented instructions.
answered 18 hours ago
manassehkatz
1,361111
Wikipedia claims that, historically, a byte wasn't necessarily eight bits.
– David Richerby
16 hours ago
@DavidRicherby Correct. But OP said things like "I was looking for examples where 8 bits is not significant" so I think a non-multiple-of-8-bit-word system counts, even if the manufacturer uses the word "byte" as long as they don't use "byte" to refer to "8 bits".
– manassehkatz
16 hours ago
Thanks for the example of a byte that was not 8 bits.
– badjohn
17 mins ago
add a comment |Â
up vote
7
down vote
up vote
7
down vote
Univac 36-bit
The Univac 1100/2200 series used a 36-bit word. Many models had functions to work with a word as 4 9-bit "bytes" - using the term byte but fitting your definition of a non-byte computer based on not using 8-bit bytes. I had a few courses on an 1100/80 at the University of Maryland in the early 80s.
The 2200 series appears to have carried on the 36-bit architecture, which in theory means up to at least 1997 according to the Wikipedia article. But the ClearPath series, while compatible with the 1100/2200, also included Xeon which would, by definition, mean it included plenty of 8-bit byte oriented instructions.
answered 18 hours ago
manassehkatz
1,361111
Univac 36-bit
The Univac 1100/2200 series used a 36-bit word. Many models had functions to work with a word as 4 9-bit "bytes" - using the term byte but fitting your definition of a non-byte computer based on not using 8-bit bytes. I had a few courses on an 1100/80 at the University of Maryland in the early 80s.
The 2200 series appears to have carried on the 36-bit architecture, which in theory means up to at least 1997 according to the Wikipedia article. But the ClearPath series, while compatible with the 1100/2200, also included Xeon which would, by definition, mean it included plenty of 8-bit byte oriented instructions.
answered 18 hours ago
manassehkatz
1,361111
answered 18 hours ago
manassehkatz
1,361111
answered 18 hours ago
manassehkatz
1,361111
answered 18 hours ago
manassehkatz
1,361111
1,361111
Wikipedia claims that, historically, a byte wasn't necessarily eight bits.
– David Richerby
16 hours ago
@DavidRicherby Correct. But OP said things like "I was looking for examples where 8 bits is not significant" so I think a non-multiple-of-8-bit-word system counts, even if the manufacturer uses the word "byte" as long as they don't use "byte" to refer to "8 bits".
– manassehkatz
16 hours ago
Thanks for the example of a byte that was not 8 bits.
– badjohn
17 mins ago
add a comment |Â
Wikipedia claims that, historically, a byte wasn't necessarily eight bits.
– David Richerby
16 hours ago
@DavidRicherby Correct. But OP said things like "I was looking for examples where 8 bits is not significant" so I think a non-multiple-of-8-bit-word system counts, even if the manufacturer uses the word "byte" as long as they don't use "byte" to refer to "8 bits".
– manassehkatz
16 hours ago
Thanks for the example of a byte that was not 8 bits.
– badjohn
17 mins ago
Wikipedia claims that, historically, a byte wasn't necessarily eight bits.
– David Richerby
16 hours ago
Wikipedia claims that, historically, a byte wasn't necessarily eight bits.
– David Richerby
16 hours ago
@DavidRicherby Correct. But OP said things like "I was looking for examples where 8 bits is not significant" so I think a non-multiple-of-8-bit-word system counts, even if the manufacturer uses the word "byte" as long as they don't use "byte" to refer to "8 bits".
– manassehkatz
16 hours ago
@DavidRicherby Correct. But OP said things like "I was looking for examples where 8 bits is not significant" so I think a non-multiple-of-8-bit-word system counts, even if the manufacturer uses the word "byte" as long as they don't use "byte" to refer to "8 bits".
– manassehkatz
16 hours ago
Thanks for the example of a byte that was not 8 bits.
– badjohn
17 mins ago
Thanks for the example of a byte that was not 8 bits.
– badjohn
17 mins ago
add a comment |Â
up vote
3
down vote
The PDP-8 and its derivatives were 12-bit machines using (at least sometimes) 6-bit characters. While the last actual PDP-8 ceased production in 1980, by that time other systems existed that used microprocessors based on the architecture, and they continued to be produced for many years (the DECmate word processing system, for example, was produced until 1990). Also, as many PDP-8s found their way into industrial control systems and other applications that change infrequently, they have been very long-lived. It's not clear to me whether any are still in actual production use today, but certainly they were in use relatively recently, and this site suggests they were definitely in use as recently as 2000.
answered 14 hours ago
Jules
7,97312142
add a comment |Â
up vote
3
down vote
The PDP-8 and its derivatives were 12-bit machines using (at least sometimes) 6-bit characters. While the last actual PDP-8 ceased production in 1980, by that time other systems existed that used microprocessors based on the architecture, and they continued to be produced for many years (the DECmate word processing system, for example, was produced until 1990). Also, as many PDP-8s found their way into industrial control systems and other applications that change infrequently, they have been very long-lived. It's not clear to me whether any are still in actual production use today, but certainly they were in use relatively recently, and this site suggests they were definitely in use as recently as 2000.
answered 14 hours ago
Jules
7,97312142
add a comment |Â
up vote
3
down vote
up vote
3
down vote
The PDP-8 and its derivatives were 12-bit machines using (at least sometimes) 6-bit characters. While the last actual PDP-8 ceased production in 1980, by that time other systems existed that used microprocessors based on the architecture, and they continued to be produced for many years (the DECmate word processing system, for example, was produced until 1990). Also, as many PDP-8s found their way into industrial control systems and other applications that change infrequently, they have been very long-lived. It's not clear to me whether any are still in actual production use today, but certainly they were in use relatively recently, and this site suggests they were definitely in use as recently as 2000.
answered 14 hours ago
Jules
7,97312142
The PDP-8 and its derivatives were 12-bit machines using (at least sometimes) 6-bit characters. While the last actual PDP-8 ceased production in 1980, by that time other systems existed that used microprocessors based on the architecture, and they continued to be produced for many years (the DECmate word processing system, for example, was produced until 1990). Also, as many PDP-8s found their way into industrial control systems and other applications that change infrequently, they have been very long-lived. It's not clear to me whether any are still in actual production use today, but certainly they were in use relatively recently, and this site suggests they were definitely in use as recently as 2000.
answered 14 hours ago
Jules
7,97312142
edited 14 hours ago
answered 14 hours ago
Jules
7,97312142
answered 14 hours ago
Jules
7,97312142
answered 14 hours ago
Jules
7,97312142
7,97312142
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The Intel 4040 processor may well have been the last commonly used sub-8bit processor. Intel produced this series 1974 and 1981. It had a 4-bit architecture (i.e. register size) and generally used Binary Coded Decimal (BCD) arithmetic and I/O. (Diagram from Wikipedia)
As to last computer in active use, who knows? There are definitely working examples of several of these architectures in places like https://livingcomputers.org
P.S. Other 4-bit processors are still available for purchase today, e.g. Renesas 4508 group.
answered 12 hours ago
Burt_Harris
18114
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Thanks. I didn't ask for last in active use as I realised that it would impossible to answer. I had hoped that the last to be launched or sold would be possible.
– badjohn
15 mins ago
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The Intel 4040 processor may well have been the last commonly used sub-8bit processor. Intel produced this series 1974 and 1981. It had a 4-bit architecture (i.e. register size) and generally used Binary Coded Decimal (BCD) arithmetic and I/O. (Diagram from Wikipedia)
As to last computer in active use, who knows? There are definitely working examples of several of these architectures in places like https://livingcomputers.org
P.S. Other 4-bit processors are still available for purchase today, e.g. Renesas 4508 group.
answered 12 hours ago
Burt_Harris
18114
New contributor
Burt_Harris is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Thanks. I didn't ask for last in active use as I realised that it would impossible to answer. I had hoped that the last to be launched or sold would be possible.
– badjohn
15 mins ago
add a comment |Â
up vote
1
down vote
up vote
1
down vote
The Intel 4040 processor may well have been the last commonly used sub-8bit processor. Intel produced this series 1974 and 1981. It had a 4-bit architecture (i.e. register size) and generally used Binary Coded Decimal (BCD) arithmetic and I/O. (Diagram from Wikipedia)
As to last computer in active use, who knows? There are definitely working examples of several of these architectures in places like https://livingcomputers.org
P.S. Other 4-bit processors are still available for purchase today, e.g. Renesas 4508 group.
answered 12 hours ago
Burt_Harris
18114
New contributor
Burt_Harris is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
The Intel 4040 processor may well have been the last commonly used sub-8bit processor. Intel produced this series 1974 and 1981. It had a 4-bit architecture (i.e. register size) and generally used Binary Coded Decimal (BCD) arithmetic and I/O. (Diagram from Wikipedia)
As to last computer in active use, who knows? There are definitely working examples of several of these architectures in places like https://livingcomputers.org
P.S. Other 4-bit processors are still available for purchase today, e.g. Renesas 4508 group.
answered 12 hours ago
Burt_Harris
18114
New contributor
Burt_Harris is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited 11 hours ago
answered 12 hours ago
Burt_Harris
18114
New contributor
Burt_Harris is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
answered 12 hours ago
Burt_Harris
18114
answered 12 hours ago
Burt_Harris
18114
18114
New contributor
Burt_Harris is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
Burt_Harris is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Burt_Harris is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Thanks. I didn't ask for last in active use as I realised that it would impossible to answer. I had hoped that the last to be launched or sold would be possible.
– badjohn
15 mins ago
add a comment |Â
Thanks. I didn't ask for last in active use as I realised that it would impossible to answer. I had hoped that the last to be launched or sold would be possible.
– badjohn
15 mins ago
Thanks. I didn't ask for last in active use as I realised that it would impossible to answer. I had hoped that the last to be launched or sold would be possible.
– badjohn
15 mins ago
Thanks. I didn't ask for last in active use as I realised that it would impossible to answer. I had hoped that the last to be launched or sold would be possible.
– badjohn
15 mins ago
add a comment |Â
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3
A lot of modern DSPs (e.g. TI TMS 32000 series) use "bytes" that have 16 bits: processors.wiki.ti.com/index.php/…
– tofro
22 hours ago
2
Many Harvard type CPUs use different size for programm and data memory, so PICs can be had in 12, 14 and 16 bit program word size. If your question is about Von Neumann machines, then we need to seperate between (logic) byte addressing and physical interface - for example modern x86 CPUs have a physical interface of 8 or more bytes wide, while on a locical level they operate bytewise. and so on. There's no real answer to that.
– Raffzahn
22 hours ago
6
"byte" and "character" didn't always mean the same thing on word-addressable computers. For example the CDC 6600, 7600, and the early Cyber series word-addressable machines had 60-bit words divided into 5 12-bit bytes, but characters were 6 bits, with 10 to a word. There were machine code instructions that operated on bytes, but accessing a single character needed a sequence of shift and mask instructions.
– alephzero
22 hours ago
6
4-bit microcontrollers are still sold today so arguably the last computer hasn't been made yet.
– Ken Gober
16 hours ago
3
Note that defining bytes as 8 bits wasn't always the norm. In languages like C++ byte is defined as the smallest addressable unit of at least 8 bits, possibly more...
– PlasmaHH
16 hours ago