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Additional techniques for finding system information

Search400 members offer advice on how to best find system info before upgrading.

In a previous tech tip, I discussed how to retrieve some critical information that vendors, especially IBM, require...

for software and hardware purchases and upgrades. In that tip, I expressed my displeasure at some usual techniques for finding two pieces of information -- amount of working memory and amount of free DASD (hard drive space) -- and petitioned Search400 readers for other ways to retrieve this information.

To your credit, you responded and I received no fewer than twenty different e-mails detailing alternative ways to find these two items. Here, then, are some reader suggestions (along with my own comments and additions) for determining the amount of working memory as well as the total and free DASD on a system.

 Amount of working memory (Main Storage) - By far, the most popular technique was to use the Work with Shared Pools (WRKSHRPOOL) command to retrieve this value. While WRKSHRPOOL is used to allocate your main memory between a maximum of 64 different storage pools in OS/400 V4R5 and V5R1, many readers pointed out that the total amount of main storage is listed right at the top of the WRKSHRPOOL screen. WRKSHRPOOL displays this information correctly for both partitioned and non-partitioned iSeries and AS/400 machines; when used in an AS/400 partition, WRKSHRPOOL will only show the main storage assigned to that particular partition. Since WRKSHRPOOL has been part of OS/400 for at least ten years, it is available on both CISC and RISC-based machines. And it's certainly easier than adding up total working memory by hand.

Alternatively, our readers offered two other ways to determine total main storage on non-partitioned machines. (I'll explain why these don't work on partitioned machines in a few paragraphs). But -- like the Work with System Status technique I discussed in the last tip -- each of these ways require you to total up the main storage number. The first way is to use option 4 (Work with Processor Resources) off the Hardware Resources menu (accessed by typing GO HARDWARE from the command line). To get the total main storage number, add up the individual storage amounts listed on the Main Storage Card resource entries on the Work with Processor Resources screen -- these entries are usually defined by a resource name that starts with 'MS' (i.e., MS01, MS02, etc).

The other alternative way for non-partitioned systems to retrieve the total main storage is to use the Start System Service Tools (STRSST) command and retrieve the information from the hardware service manager. To do this in OS/400 V4R5 or V5R1, perform the following steps:

- Enter the System Service Tools (SST) menu by typing in the STRSST command on the command line.

- Select option 1, Start a Service Tool
- Select option 7, Hardware service manager
- Select option 2, Logical hardware resources (buses, IOPs, controllers...)
- Select option 3, Main storage resources

This option shows the Display Main Storage Information screen, which only shows the main storage card resources (again, starting with the literal 'MS') that are dedicated to your system. As with the Hardware Resources menu, you add up the individual card totals to calculate your main storage amount.

It's important to note that these last two techniques -- Work with Processor Resources and STRSST Main Storage Resources -- don't work for partitioned machines. If you try either of these techniques for a partitioned machine, the screens will report the Main Storage Card resource entries for all partitions on the entire system, not just those assigned to the partition you're logged on to. This isn't necessarily a quirk because these screens show the Main Storage resources that are available, not those that are assigned to a particular partition (and in a partitioned system, you can reassign main storage between partitions). For best Main Storage reporting, be sure to use the WRKSHRPOOL technique with partitioned machines (besides it's easier).

 Amount of Free DASD (hard drive space) - Outside of the calculation I provided in the last tip, the best option for determining free DASD is contained on the Disk Space Tasks menu (which is reached by typing GO DISKTASKS on a command line). On that menu, select option 2, Print Disk Space Information, and this will produce a Disk Space report in spool file format QPEZDISK. This report shows you the amount of DASD used for several different OS/400 functions (User libraries, user directories, IBM libraries, etc), as well as the total percentage of the system DASD each function is using. Total up all the different sizes (except for the Unused space category), and that will show you the amount of free DASD available on your system. This report is handy and more valuable than the manual calculation I listed last time because it provides more granular information on how much storage is used by a number of different functions.

Finding system information on an OS/400 can be a drag sometimes. However if you know the right places to look, this job gets a lot easier.

About the author: Joe Hertvik is an IT professional and freelance writer who has been working with OS/400 since the days of the System/38 in the mid-1980s. Joe can be reached at


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This was last published in May 2002

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