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Thread: IBM I-Series (AS/400) questions

  1. #1
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    Default IBM I-Series (AS/400) questions

    I used to work in environments where the IBM AS/400 was on the intranet but never really got a chance to do more than connect to one of the databases. From what I gather they are quite different from the PCs and workstations with which I am more familiar.

    Having read the post about the pre-I-Series AS/400s, I'd like to ask for your input on the I-Series. Not wishing to add another doorstop to my collection, I need to know where the hurdles are: Is there a common OS for all models, or machine-specific? Is the OS readily available? Are there dedicated peripherals required; keyboard, monitor, storage, network interface? What was considered a "reasonable" configuration in the environment for which it was intended?

    By the way, I believe I have a complete set of AS/400 documentation for the pre-I-series. Version 3, circa 1997, all sealed. Came with Client Access CD. Bought it on eBay a few years ago.

    -CH-

    CD.jpg

  2. #2
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    You may find this useful:
    http://ps-2.kev009.com/as400/

  3. #3
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    Thank you for the suggestion.

    -CH-

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    Quote Originally Posted by clh333 View Post
    Thank you for the suggestion.

    -CH-
    In case you're not aware:
    Twinax console = 5250 series
    HMC = Hardware Management Console (using DCAF, Distributed Console Access Facility). This can be a PC or PS/2 with the appropriate LAN support, 5250 adapter/Ethernet adapter depending, and the DCAF software too.

  5. #5
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    Completely clueless, thanks. I won't be taking the plunge until I have a lot more information, and every bit helps. Especially useful is the suggestion to look for a server with software.

    The 5250 was apparently heavy, at 79#, and seems to have been superseded by an emulation card (ISA or MicroChannel) and software, plus the appropriate cable adapter, I suppose. Apparently this can allow a PC to serve as a console and HMC for the server. TwinData http://www.twindata.com/ also supplies consoles and adapters for the iSeries and more.

    Twinax had a limit of seven addressable devices, I read, and used Manchester (binary phase) encoding. When - how late in the game - was twinax supplanted by Ethernet in the iSeries?

    Thanks again for your help.

    -CH-

  6. #6
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    I'm sorry, I'm a mainframe and networking guy. I know of IBM Midrange and Office Systems and most terminology, but I never worked on/with the AS/400 series. 3790 and 8100 Office Systems (DPCX and DPPX OSes), yes, but only in relation to connectivity to the S/370 system(s). Timeline info about the AS/400 Midrange Systems might better be asked in a post on NG comp.sys.ibm.as400(.misc), as well as for other details.

    Just had a quick look, it's pretty inactive in there now (nothing since 2004?). But I did find this:
    https://groups.google.com/forum/#!to...00/WkjJvsj_65s
    Last edited by WBST; November 30th, 2019 at 10:30 AM.

  7. #7

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    I worked for IBM for many years, and a good portion of that time was writing operating system code and supporting iSeries customers. My memory is fading as I've been gone from the iSeries now for almost 15 years, but there are some quick answers.

    The OS that you can install depends on the model of the machine. When a new model is released it runs the current OS and generally gets five years of updates. The first PowerPC versions came with V3R6, and maybe you can get them to V4R5 or V5R1. Newer machines start at a later OS and end off at a later OS. IBM should have tables published so that you can figure out exactly what you can install based on the model number.

    I don't know how the OS is licensed, but it definitely is licensed and it does license key checks to enforce it. Before you adopt a machine be sure to see if it has license keys. This isn't like DOS; you can't go find an old copy and install it on abandonware sites, and if you do find an older copy and try to install it you might get caught by the license key checks.

    Peripherals ... it depends on the machine but basically all proprietary to the machine. You don't need a real 5250 model terminal; 5250 is both the name of the protocol and the model number of the first terminal. There are modern versions of 5250 terminals that don't weigh metric tonnes, although the original 5250 is beautiful. (And widely sought after by keyboard hunters.) Later machines allow you to skip the physical terminal entirely and use an HMC (hardware maintenance console), serial port, or Ethernet to get a console.

    Hard drives were SCSI and were formatted to 520 bytes per sector. You need hard drives with a specific AS/400 firmware and VPD on them.

    My personal choice for an AS/400 would be an older 150 model (compact deskside) or an 820 model (fat deskside). The 820s were very capable machines, and could even be partitioned to run Linux as a guest of OS/400. The key thing is going to be license keys for the OS, compilers and other software.

  8. #8
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    Twinax had a limit of seven addressable devices, I read,
    Per channel, yes. I don't think I've ever seen a configuration that only had just one channel. Most typically had three or four and my (basketcase) 720 has sixteen channels, so it can handle a LOT of Twinax peripherals.
    It also hung around for quite a while due to legacy installations, though by the late portion of the game Ethernet was coming online and most users had replaced classic twinax cabling with baluns and twisted pair CAT5.
    Canadian Tire ran like this until 2011 or so.

  9. #9

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    The iSeries and pSeries hardware are identical, but they have changed the model number in firmware to keep you from trying to run the system software from one on the other. For example in the power 5 era, the was a P5-570 that was a 9117-570 and an I5-570 that was a 9406-570, but the hardware was exactly the same. The bigger systems like the 570 required an HMC to even really power them on. If you tried to power them on via the control panel, the hardware might power up, but it probably won't start any of the LPARs. You could download HMC software from IBM at the time, and the HMC was basically a cheap xSeries server, but just like before, they changed the model number. It was just linux software, and if you were persistent enough you could install it and make it work, I don't recall really exactly what I had to do, but it was trivial. Later, if it would reboot, it would complain and you'd have to hold it's hand to get it going again. They don't really need to reboot all that often though. I remember using the HMC at a customer's site and it was kind of sluggish, so I rebooted it, and linux force an fsck because it had been like 1300 days since the last check. The reboot did fix the sluggishness too.

  10. #10
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    Thank you, one and all, for your responses. Occasionally I will page through eBay offerings of AS400 machines to see what's available but my lack of knowledge is usually matched by that of the "resellers". I imagine they too consult eBay to see what they can get for a machine they found in a warehouse somewhere. I'm going to need to find another source; if anyone knows of an orphan please pull my coat.

    I have no need for an AS400 except to satisfy my curiosity, and for the fact that I can't afford to dedicate the space or resources to a mainframe. My wife already thinks I'm nuts and after driving 1400 miles to New Hampshire and back to retrieve an E-size plotter, I may have to agree with her. My refuge lies in the phrase "Life is for learning" and the fact that I'm still alive (in spite of my ignorance).

    Thanks again, I'll report back when I know more.

    -CH-

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