Getting started with the Hardware

From Try-AS/400
Jump to navigation Jump to search

IBM has build many different AS/400 systems over the course of the last 30 years, usually with increasing speed. Speed was given by IBM terms of CPW, Commercial Processing Workload. This is a relative number to compare systems to a well defined very early and thus outdated AS/400 system.[1]

Authoritative source for all questions regarding hardware and expansion capabilities are the System Builder manuals from IBM. Early documents are grouped by OS Release Versions, later ones by Processor Technology (POWER6, etc.).

Console Considerations

To be really independent from third parties, I strongly urge to get a proper console. It's a life saver when things go wrong with TCP/IP. Additionally, some tasks need OS/400 running in a restricted state, somewhat similar to the single user mode of UNIX. Both are used for maintenance, OS/400 needs this mode for creating a proper full backup of the machine.

Depending on the age of the hardware, you need:

  • A twinax controller (usually included in the system),
  • A twinax brick, some kind of breakout box from D-Subminiature connector to multiple twinax-ports on the brick,
  • A twinax cable with connectors on each end,
  • A twinax-display adapter, a kind of Y-adapter with two twinax-ports and one D-Subminiature 15-Pin for attaching the
  • 5250 compatible terminal,
  • Keyboard for the 5250-Terminal.[2]

Alternatively, there exist(ed) ISA and PCI cards with a D-Subminiature 15-Pin Port for placing in a PC. With the mentioned Y-adapter, accompanying software and the right settings, this solutions exactly performs like a hardware console.

Newer hardware features other ways to get access to a console, most often LAN Console. It is a mess of IBM i Access for Windows client component and stuff you'll need to configure in DST.[3] DST is only accessible after an initial install. So if you have a blank machine you need to install from scratch, possibilities are somewhat limited.

Even newer hardware (Example: P520 Express 19" rack mount server) features the necessity of a Hardware Management Console, sold most often as an IBM ThinkPad™ running a heavily customized Red Hat Linux, with a focus on management of many servers. A heap of Java programs provides HTML output to an also installed old version of Firefox, providing a crude web UI allowing to configure machines (create LPARs, move hardware between these virtual instances, manage firmware PTFs, and more. Also, after starting an LPAR, one can attach an integrated tn5250 client as console, allowing to install such a machine from scratch.

Also, certain versions of the HMC are offered by IBM as a virtual appliance, either for POWER LPARs or for x86 based systems, running VMware ESXi and other Hypervisors.

Hardware setup

Dependent on the provided accessories, you'll just wire power cord to a proper outlet and and the ethernet port[4] to a hub or switch.

If console accessories are available, cable these like outlined in the accessories chapter.

Preparation before power on

All AS/400 have a LC-Display with alphanumeric display capability somewhere at the front, a few push buttons and an amber Attention-LED for signaling of severe system errors. Older hardware additionally has one or more LEDs for indicating main processor activity. One steers the service processor in the machine with the front panel and can read system status from it. Please don't play blinkenlights with it. Since there are just three knobs, timing dependent keypress-expressions are used for certain functions you may accidentally trigger. Some of them modify parameters permanent and may lock you out of your system.

The most needed functions are:

  • Selection from where the next IPL (boot) should happen, and how (automatic full boot or manual boot into a restricted state),
  • Visualization of what the machine's currently doing when booting or shutting down via a so called system reference code.

Again, having a system console is strongly advised. It is not necessary to keep it connected all the time, though. If your machine came readily installed, has a known IP address in your LAN and cleanly boots in unattended mode, you're fine without a console. For a while.

Booting the machine

Given a readily installed machine, IPLing is relatively easy:

  • Turn on the console display, if available.[5] After CRT-warmup, the cursor will blink at you top right.
  • Verify that the LCD shows
 01   B N
  • Press the power-on-off button (vertical line within a circle) momentarily,
  • Be patient. IPL can take anywhere from about under 10 Minutes up to 45 Minutes or more, depending on
    • Machine speed, that is dependent on machine age and hard disk count,
    • Machine state: Powered down cleanly or just has being plug-pulled,
    • Count of configuration objects and data tables.

The machine will awake and the service processor performs basic hardware checks, spins up it's disks, does an enormous amount of self-tests and finally commits control to the main processor. This is most visible in that the main processor LED will light up and show CPU activity.

Each IPL step is accompanied by a SRC displayed on the LCD. If the machine seems stuck at one point (display content hasn't changed for more than two minutes), one might search online for the actual meaning of the displayed SRC and derive recovery steps from that information. MCPRESS has an excellent Article regarding IPL steps, Secrets of IPLs Exposed.

After a few minutes, an attached console will move the cursor to the top left position that means that the twinax controller in the AS/400 has been initialized. After a while the console will show activity by outputting SRC and an textual explanation what's going on, parallel to the LCD.

At the end of the IPL, an attached console will show the signon screen. The machine will be comparably slow at this point because it's (still) starting background jobs. Access with tn5250 is not possible at this point, because ICP/IP services have not been started yet.

After about 5..15 Minutes, disk activity should have been mostly ceased and the processor utilization LED will be mostly off, probably just briefly flickering once per second.

Congrats, you may now try to log in (remotely).

Log in

This is usually called sign on, not log in by IBM.

Depending on that way of access you'll use to your box, you either see the signon screen on the console display. Or you need to start your tn5250 emulator software and open a connection to the IP address of your box, to be presented with the signon screen afterwards. If this is the very first tn5250 connection to the box, it may take a few seconds with rattling disks until the screen finally appears.[6]

No matter what, a very distinct feature of the AS/400 is: Everything is menu- or forms based. The login screen is a form with multiple input fields that are handled on the client side: In the not-so-dumb terminal or your emulator software. This is just like a form you'll be presented in your web browser when you register for an account for some web service: You fill out the fields locally and later click on Submit (or what the send-the-stuff button is actually called) that triggers the sending of all fields at once to the server for processing.

Same goes for all AS/400 screens. Fill out locally, send form when completed. Since there's no mouse interface, there's no submit button. Keyboard functions are a bit different as you may be used to, especially when you use a 5250 hardware terminal.

  5250 Terminal Software Emulator
Submit Form Enter (usually found at the position of the right Ctrl-Key) Enter or Return (usually user definable)
Next Field Return, Tab Tab only

Default administrative user is the security officer, QSECOFR with the same string as default for the password, if this hasn't been changed. So, fill out the user field, press the needed next field-Key and fill out the passwort. You don't see your typing to prevent spying over your shoulder to reveal your password.[7]

After a successful signon, you'll be presented with the main menu. From there we'll continue to explore the system.

Note: In a freshly installed system, QSECOFR is not allowed to sign on via remote devices, such as tn5250 sessions. This behavior is controlled by the system variables QAUTOCFG (for automatic creation of device objects), QAUTORMT (for automatic creation of network initiated connection objects) and QLMTSECOFR (for controlling access to those device objects). Thus, after an initial install, you cannot sign on as QSECOFR via tn5250 remotely without modifying those systen variables with WRKSYSVAL.



  1. Of course this makes it hard to compare application performance with systems outside the IBM universe. IBM has hesitated a long time to release actual processor speed values, because in transactional processing, processor speed is just one of many factors to determine the actual application speed, users are experiencing.
  2. Can also be utilized to beat burglars. Gives horrible nose bleeds if utilized in the right way.
  3. Roughly analog to the BIOS setup of the PC world.
  4. Common pitfall is to connect the ethernet cable to something that looks like a matching receptacle. Make sure, you don't accidentally utilize an ISDN or Token Ring port on the machine. Function expansion cards often have a four-digit-number sticker visible from outside. Do an online-search that one is Ethernet.
  5. Of course, it has to be properly wired to the machine and mains, also.
  6. OS/400 creates configuration objects on the fly for connections.
  7. Depending on your typing speed, it could be possible to see that keys you actually press to steal your password anyway.