3 ms·

I think I saw an advertisement for a 128-bit computer in an old issue of BYTE magazine. I think it was from IBM.

by zzo38computer 5y ago

mikeytown2 5y ago
I'd guess Digital Alpha (DEC) but I can't find anything mentioning it. Other guess would be Cray.
- eesmith 5y ago
  https://en.wikipedia.org/wiki/128-bit_computing https://en.wikipedia.org/wiki/128-bit_computing list contenders as IBM System/370, upgraded DEC VAX, and ICL 2900 Series.
  - karmakaze 5y ago
    The page lists these uses for 128-computing, any of which seem like sufficient motivators for it to come to pass: - The free software used to implement RISC-V architecture is defined for 32, 64 and 128 bits [...] - Universally unique identifiers (UUID) consist of a 128-bit value. - IPv6 routes computer network traffic amongst a 128-bit range of addresses. - ZFS is a 128-bit file system. - 128 bits is a common key size for symmetric ciphers [...] - The IBM i virtual instruction set defines all pointers as 128-bit. - Increasing the word size can speed up multiple precision mathematical libraries [...] - MD5 is a hash function producing a 128-bit hash value. - Apache Avro uses a 128-bit random number as synchronization marker [...]
    - eesmith 5y ago
      Those seem like poor reasons to justify 128-bit CPU hardware, over 128-bit emulation in software. In particular, MD5 use in new software is strongly discouraged. You'll note that some of them are essentially identical with https://en.wikipedia.org/wiki/256-bit_computing https://en.wikipedia.org/wiki/256-bit_computing so they seem more guided by abstract arguments than concrete engineering reasoning.
skissane 5y ago
Probably the IBM AS/400 or its predecessor the System/38, which uses 128 bit pointers. However, it has an unusual architecture in which all programs run in a bytecode-based virtual machine, comparable to Java or dotnet. The 128 bit pointers are only used in the virtual machine. The underlying physical hardware had 48 bit addressing initially (starting in the late 1970s); in the 90s they switched physical hardware to support 64 bit addressing Also, even though the pointers are 128 bit, many of the bits in the pointer are reserved for future use. Partly it was an exercise in extreme future-proofing. Partly because they use tag bits to mark valid pointers in memory (to stop programs from forging pointers), but they only have one tag bit reserved for every 16 bytes of RAM, so pointers must have 16 byte alignment.

I think I saw an advertisement for a 128-bit computer in an old issue of BYTE magazine. I think it was from IBM.

mikeytown2 5y ago

I'd guess Digital Alpha (DEC) but I can't find anything mentioning it. Other guess would be Cray.

eesmith 5y ago
https://en.wikipedia.org/wiki/128-bit_computing https://en.wikipedia.org/wiki/128-bit_computing list contenders as IBM System/370, upgraded DEC VAX, and ICL 2900 Series.
- karmakaze 5y ago
  The page lists these uses for 128-computing, any of which seem like sufficient motivators for it to come to pass: - The free software used to implement RISC-V architecture is defined for 32, 64 and 128 bits [...] - Universally unique identifiers (UUID) consist of a 128-bit value. - IPv6 routes computer network traffic amongst a 128-bit range of addresses. - ZFS is a 128-bit file system. - 128 bits is a common key size for symmetric ciphers [...] - The IBM i virtual instruction set defines all pointers as 128-bit. - Increasing the word size can speed up multiple precision mathematical libraries [...] - MD5 is a hash function producing a 128-bit hash value. - Apache Avro uses a 128-bit random number as synchronization marker [...]
  - eesmith 5y ago
    Those seem like poor reasons to justify 128-bit CPU hardware, over 128-bit emulation in software. In particular, MD5 use in new software is strongly discouraged. You'll note that some of them are essentially identical with https://en.wikipedia.org/wiki/256-bit_computing https://en.wikipedia.org/wiki/256-bit_computing so they seem more guided by abstract arguments than concrete engineering reasoning.

skissane 5y ago

Probably the IBM AS/400 or its predecessor the System/38, which uses 128 bit pointers. However, it has an unusual architecture in which all programs run in a bytecode-based virtual machine, comparable to Java or dotnet. The 128 bit pointers are only used in the virtual machine. The underlying physical hardware had 48 bit addressing initially (starting in the late 1970s); in the 90s they switched physical hardware to support 64 bit addressing Also, even though the pointers are 128 bit, many of the bits in the pointer are reserved for future use. Partly it was an exercise in extreme future-proofing. Partly because they use tag bits to mark valid pointers in memory (to stop programs from forging pointers), but they only have one tag bit reserved for every 16 bytes of RAM, so pointers must have 16 byte alignment.