4 ms·

Is IBM i the thing formerly known as AS/400? IBM's new shiny next-millennium single letter branding is more confusing than their old-school letters-virgule-numb

Is IBM i the thing formerly known as AS/400? IBM's new shiny next-millennium single letter branding is more confusing than their old-school letters-virgule-numbers branding.

mushufasa 3y ago
yes
chrisstanchak 3y ago
pwrdwnsys *immed
- jasomill 3y ago
  CPF222E - *JOBCTL special authority is required.
CoastalCoder 3y ago
TIL the word "virgule".
- speed_spread 3y ago
  I'm not sure this is proper usage. Virgule is French for Comma, not Slash. And to my knowledge, there is no French equivalent for Slash and if there is, it's not commonly used.
  - bitwize 3y ago
    I wasn't speaking French, I was speaking English, in which virgule means slash.
    - CoastalCoder 3y ago
      > I wasn't speaking French, I was speaking English, in which virgule means slash. It seems like you and GP both have valid points. Borrow-words usually (AFAIK) generally have the same meaning in the donor and recipient languages. So referring to the donor-language definition is a good way to figure out intended usage. IIUC, virgule has different meanings in Latin, French, and English. I'm guessing that's what's throwing us off.
hindsightbias 3y ago
2008
deleted 3y ago
[deleted]
skissane 3y ago
Yes, but it also reflects the fact that it is no longer a separate hardware line. In the beginning (1978) was the IBM System/38, which had a custom CISC CPU architecture with 48-bit addressing (called IMPI), vaguely resembling the 360/370 mainframe instruction set, but incompatible with it, and having some rather high-level abilities like task switching in microcode (similar to hardware task switching on the 386). The System/38 had some very advanced features: single level storage, capabilities and programs compiled to byte code (which the OS then converted to the IMPI physical instruction set). However, IBM also had its System/36 "midrange" line (basically minicomputers but IBM preferred to call their business-oriented minicomputers "midrange"), which was incompatible and more of a traditional system architecture. So in 1988 IBM "unified" them by releasing the AS/400, which was basically a version 2.0 of the System/38, keeping the same basic architecture but adding a System/36 emulation subsystem so it could run most System/36 applications. Separately, IBM had its RISC Unix RS/6000 line, which spawned POWER and PowerPC. And then in 1991, IBM came out with a new version of the AS/400 based on PowerPC instead of proprietary IMPI CISC. The fact that applications compiled to bytecode meant most applications could be ported to RISC seamlessly, since the new OS version translated the bytecode to PowerPC instructions instead of IMPI instructions. At the same time, much of the core of the OS was rewritten in C++ (having previously been in a proprietary PL/I dialect.) But still, although RS/6000 and AS/400 now used the same CPU architecture, they were still physically different hardware. Originally, the AS/400 used its own PowerPC chips with additional instructions the RS/6000 ones lacked. Even after they unified the two lines on the same CPU models, they still had different firmware. In 2000, there was a marketing-driven decision ("eServer") to rebrand RS/6000 to pSeries and AS/400 to iSeries. This was part of an attempt to present IBM's four distinct server platforms (mainframe, AS/400, RS/6000 and PC) as some kind of cohesive strategy (mainframe became zSeries and PC servers became xSeries). Then, in 2006, the iSeries (formerly AS/400) and pSeries (formerly RS/6000) hardware lines were merged completely, to become IBM Power Systems. Now there was no physical difference between the hardware, it is just which OS you install on it. The IBM i (originally OS/400 and later i5/OS) operating system uses certain firmware features which AIX doesn't use – but all IBM Power Systems have that code in their firmware, it is just AIX and Linux don't call those functions. (There are now low-end Linux only machines which refuse to run AIX or IBM i, although possibly that's just a flag in the firmware license as opposed to distinct code.)
hlandau 3y ago
One of the most interesting things about IBM i/AS/400 is its use of hardware memory tagging. There is a secret set of extensions to the PowerPC ISA which allows you to associate a tag bit with every 16 bytes of memory. This is used to implement a capability-based model where valid pointers can't be forged. I write some more about it here: https://www.devever.net/~hl/ppcas https://www.devever.net/~hl/ppcas Interestingly this functionality is actually unlocked on the Raptor Talos II/Blackbird systems so you can play with it in full.
- pdw 3y ago
  It's amazing that (if I understand it correctly) the entire security of the system rests on the user not being able to execute arbitrary code. One wrong-code bug in the (privileged) compiler backend and it all falls down.
  - skissane 3y ago
    In practice, it doesn't matter so much, because IBM i is an (ever-increasingly fringe) server platform for business applications, so the odds of malicious code ever making their way on to the system is much less than for an OS used for more general purpose computing But you are right, and in that it has something in common with sandboxing of Java applets, for example – which didn't work out as well as its inventors had hoped. That said, although classic applications all run in a single shared address space, newer versions have added support for isolated per-process address spaces (teraspaces), which have in turn used been to add an AIX compatiblity layer (PASE). If you write your apps against AIX compatibility layer, you get process-based security just like you do on AIX. And in that layer you aren't just limited to calling (a subset of) AIX APIs, you can also call into IBM i native APIs which don't exist on AIX – albeit at some performance cost, since the call has to be marshalled into the single shared address space. IBM's original JVM ran in the classic single shared address space, and was deeply integrated into the OS. Then they replaced it with J9, their JVM for AIX/Linux/Windows/etc, and J9 runs under the AIX compatibility layer. Given they encourage Java for developing new apps – a lot of apps now contain a mixture of legacy RPG/COBOL/etc code along with Java code to implement web UIs and SOAP/REST APIs – more and more stuff is running outside of the shared address space.
kitd 3y ago
Tbf, that shiny new branding is about 25 years old now.
jonathaneunice 3y ago
IBM I and Z (each with a dizzying array of branding zigs and zags going back decades) are both pretty interesting technologically. I has a fancy memory architecture, very smart disk controllers (essentially distributed intelligence, like an octopus), a virtual instruction set (that has been used multiple times to almost seamlessly jump huge under-the-hood processor changes), and historically a reliability record second to none (the old box in the wiring closet running for years upon years, completely untended). Z has even more toys, including some of the strongest clustering, partitioning, security found anywhere. Sysplex, LPARs, and RACF are all impressive, especially given how many decades ago they started. We won't even talk about the DBMS and transaction monitors, which are their own brand of crazy strong. Those immersed in the higher-volume, standard microprocessor, Unix/Linux or Windows, cloud mainstream don't give "proprietary systems" much thought or respect. But we probably should. Those who knew the IBM I or Z, or the DEC VAX/VMS, HP MPE, Tandem NonStop, etc.—they were too expensive, too few in number, too quirky—but what they did well, they did outstandingly well in their purpose-focused, allopatrically speciated ways. Better in many cases that we can do today with the latest 2024 gear.
- krylon 3y ago
  > they were too expensive I think this is the biggest problem, plus the fact these systems tend to be tied to proprietary - and also very expensive - hardware platforms. If I want to learn about GNU/Linux or BSD, all I need is a computer (PC in most cases, but other options exist) and an Internet connection. These days, most people (at least in Europe and North America) have these anyway, so it's really easy to get started in the comfort of one's own home. Having a free account on a public machine is cool, but it's not the same as having your own system, especially if you want to learn about system administration.
- electroly 3y ago
  > too expensive The killer, of course. As they say: anyone can build a bridge that stands, but it takes an engineer to build a bridge that barely stands. In this game, a solution that's too expensive is often not a solution at all.
sillywalk 3y ago
Here's a link to Inside the AS/400 by Frank Soltis, one of the lead designers. It's an interesting introduction to the AS/400, up to the POWER transition. There's also Fortress Rochester by the same author that goes into the iSeries / POWER4, but I haven't found a copy on line. https://archive.org/details/insideas4000000solt/ https://archive.org/details/insideas4000000solt/

Is IBM i the thing formerly known as AS/400? IBM's new shiny next-millennium single letter branding is more confusing than their old-school letters-virgule-numbers branding.

mushufasa 3y ago

yes

chrisstanchak 3y ago

pwrdwnsys *immed

jasomill 3y ago
CPF222E - *JOBCTL special authority is required.

CoastalCoder 3y ago

TIL the word "virgule".

speed_spread 3y ago
I'm not sure this is proper usage. Virgule is French for Comma, not Slash. And to my knowledge, there is no French equivalent for Slash and if there is, it's not commonly used.
- bitwize 3y ago
  I wasn't speaking French, I was speaking English, in which virgule means slash.
  - CoastalCoder 3y ago
    > I wasn't speaking French, I was speaking English, in which virgule means slash. It seems like you and GP both have valid points. Borrow-words usually (AFAIK) generally have the same meaning in the donor and recipient languages. So referring to the donor-language definition is a good way to figure out intended usage. IIUC, virgule has different meanings in Latin, French, and English. I'm guessing that's what's throwing us off.

hindsightbias 3y ago

2008

deleted 3y ago

[deleted]

skissane 3y ago

Yes, but it also reflects the fact that it is no longer a separate hardware line. In the beginning (1978) was the IBM System/38, which had a custom CISC CPU architecture with 48-bit addressing (called IMPI), vaguely resembling the 360/370 mainframe instruction set, but incompatible with it, and having some rather high-level abilities like task switching in microcode (similar to hardware task switching on the 386). The System/38 had some very advanced features: single level storage, capabilities and programs compiled to byte code (which the OS then converted to the IMPI physical instruction set). However, IBM also had its System/36 "midrange" line (basically minicomputers but IBM preferred to call their business-oriented minicomputers "midrange"), which was incompatible and more of a traditional system architecture. So in 1988 IBM "unified" them by releasing the AS/400, which was basically a version 2.0 of the System/38, keeping the same basic architecture but adding a System/36 emulation subsystem so it could run most System/36 applications. Separately, IBM had its RISC Unix RS/6000 line, which spawned POWER and PowerPC. And then in 1991, IBM came out with a new version of the AS/400 based on PowerPC instead of proprietary IMPI CISC. The fact that applications compiled to bytecode meant most applications could be ported to RISC seamlessly, since the new OS version translated the bytecode to PowerPC instructions instead of IMPI instructions. At the same time, much of the core of the OS was rewritten in C++ (having previously been in a proprietary PL/I dialect.) But still, although RS/6000 and AS/400 now used the same CPU architecture, they were still physically different hardware. Originally, the AS/400 used its own PowerPC chips with additional instructions the RS/6000 ones lacked. Even after they unified the two lines on the same CPU models, they still had different firmware. In 2000, there was a marketing-driven decision ("eServer") to rebrand RS/6000 to pSeries and AS/400 to iSeries. This was part of an attempt to present IBM's four distinct server platforms (mainframe, AS/400, RS/6000 and PC) as some kind of cohesive strategy (mainframe became zSeries and PC servers became xSeries). Then, in 2006, the iSeries (formerly AS/400) and pSeries (formerly RS/6000) hardware lines were merged completely, to become IBM Power Systems. Now there was no physical difference between the hardware, it is just which OS you install on it. The IBM i (originally OS/400 and later i5/OS) operating system uses certain firmware features which AIX doesn't use – but all IBM Power Systems have that code in their firmware, it is just AIX and Linux don't call those functions. (There are now low-end Linux only machines which refuse to run AIX or IBM i, although possibly that's just a flag in the firmware license as opposed to distinct code.)

hlandau 3y ago

One of the most interesting things about IBM i/AS/400 is its use of hardware memory tagging. There is a secret set of extensions to the PowerPC ISA which allows you to associate a tag bit with every 16 bytes of memory. This is used to implement a capability-based model where valid pointers can't be forged. I write some more about it here: https://www.devever.net/~hl/ppcas https://www.devever.net/~hl/ppcas Interestingly this functionality is actually unlocked on the Raptor Talos II/Blackbird systems so you can play with it in full.

pdw 3y ago
It's amazing that (if I understand it correctly) the entire security of the system rests on the user not being able to execute arbitrary code. One wrong-code bug in the (privileged) compiler backend and it all falls down.
- skissane 3y ago
  In practice, it doesn't matter so much, because IBM i is an (ever-increasingly fringe) server platform for business applications, so the odds of malicious code ever making their way on to the system is much less than for an OS used for more general purpose computing But you are right, and in that it has something in common with sandboxing of Java applets, for example – which didn't work out as well as its inventors had hoped. That said, although classic applications all run in a single shared address space, newer versions have added support for isolated per-process address spaces (teraspaces), which have in turn used been to add an AIX compatiblity layer (PASE). If you write your apps against AIX compatibility layer, you get process-based security just like you do on AIX. And in that layer you aren't just limited to calling (a subset of) AIX APIs, you can also call into IBM i native APIs which don't exist on AIX – albeit at some performance cost, since the call has to be marshalled into the single shared address space. IBM's original JVM ran in the classic single shared address space, and was deeply integrated into the OS. Then they replaced it with J9, their JVM for AIX/Linux/Windows/etc, and J9 runs under the AIX compatibility layer. Given they encourage Java for developing new apps – a lot of apps now contain a mixture of legacy RPG/COBOL/etc code along with Java code to implement web UIs and SOAP/REST APIs – more and more stuff is running outside of the shared address space.

kitd 3y ago

Tbf, that shiny new branding is about 25 years old now.

jonathaneunice 3y ago

IBM I and Z (each with a dizzying array of branding zigs and zags going back decades) are both pretty interesting technologically. I has a fancy memory architecture, very smart disk controllers (essentially distributed intelligence, like an octopus), a virtual instruction set (that has been used multiple times to almost seamlessly jump huge under-the-hood processor changes), and historically a reliability record second to none (the old box in the wiring closet running for years upon years, completely untended). Z has even more toys, including some of the strongest clustering, partitioning, security found anywhere. Sysplex, LPARs, and RACF are all impressive, especially given how many decades ago they started. We won't even talk about the DBMS and transaction monitors, which are their own brand of crazy strong. Those immersed in the higher-volume, standard microprocessor, Unix/Linux or Windows, cloud mainstream don't give "proprietary systems" much thought or respect. But we probably should. Those who knew the IBM I or Z, or the DEC VAX/VMS, HP MPE, Tandem NonStop, etc.—they were too expensive, too few in number, too quirky—but what they did well, they did outstandingly well in their purpose-focused, allopatrically speciated ways. Better in many cases that we can do today with the latest 2024 gear.

krylon 3y ago
> they were too expensive I think this is the biggest problem, plus the fact these systems tend to be tied to proprietary - and also very expensive - hardware platforms. If I want to learn about GNU/Linux or BSD, all I need is a computer (PC in most cases, but other options exist) and an Internet connection. These days, most people (at least in Europe and North America) have these anyway, so it's really easy to get started in the comfort of one's own home. Having a free account on a public machine is cool, but it's not the same as having your own system, especially if you want to learn about system administration.
electroly 3y ago
> too expensive The killer, of course. As they say: anyone can build a bridge that stands, but it takes an engineer to build a bridge that barely stands. In this game, a solution that's too expensive is often not a solution at all.

sillywalk 3y ago

Here's a link to Inside the AS/400 by Frank Soltis, one of the lead designers. It's an interesting introduction to the AS/400, up to the POWER transition. There's also Fortress Rochester by the same author that goes into the iSeries / POWER4, but I haven't found a copy on line. https://archive.org/details/insideas4000000solt/ https://archive.org/details/insideas4000000solt/