The Memory Issue- by Chris Williams

How much RAM
could a Warp-RAM RAM
if a Warp-RAM could RAM RAM?

How much RAM is enough is one of the most infamous issues in the world of OS/2 Warp. Most everyone agrees the IBM recommended minimums are bare-bones amounts barely capable of a "Gee, it came up!" level of performance. After that, how much you really need seems to depend on who you ask, what you run, and how fast "fast enough" is to you.

OS/2 Warp, like other modern operating systems, plays the memory game of "Robbing Peter to pay Paul" called swapping. In simplest terms, if Warp needs a certain amount of RAM to run a program, but that RAM is not available, Warp will write (or swap) some of the data it has in RAM to the hard drive to free up that RAM for the program. The problem is, a PC hard drive is much slower to access than RAM, so there's a big performance penalty for swapping. A small amount of swapping is normal on any Warp system. Excessive swapping will slow performance to a crawl and, in extreme cases, can damage your hard drive. This is called thrashing, and should be avoided at all costs.

Benchmarks aside, empirical measurements of OS/2 system performance in various RAM configurations are pretty straight forward. Most people agree 4MB is not enough to do anything useful, 6MB is enough to get all of Warp's neat features (including HPFS) running, and 8MB can handle basic applications with an "acceptable" level of performance. Again, what is "acceptable" to one person may not be to another. Moreover, once you get used to faster performance, your own definition of "acceptable" will also probably change.

As an IS professional and long time OS/2 "Power User", I usually recommend that nobody should consider running Warp in less than 8MB of RAM. For my own taste, the more RAM you can throw at Warp, the better.

I'm also into instant computer gratification.

On the other hand, most home users I know of never push their systems hard enough to really need more than 16MB, which also happens to be a nice RAM "sweet spot" for Warp. By a RAM "sweet spot", I mean the following:

In a given system, Warp's performance increases dramatically as you increase the amount of available RAM in that system from 4MB to 8MB to 12MB. As you add RAM in these amounts, the size of the performance increase gets smaller. Basically, the economic Law of Diminishing Returns comes into play. Going from 12MB to 16MB still provides a nice speed increase, but it's not nearly the size you see going from 4MB to 8MB. After 16MB, unless you're running memory intensive applications, or like to keep more than several applications going at once, adding more RAM probably isn't going to be a big help.

Keep in mind that RAM isn't the only thing that factors into overall system performance. How fast your hard drive and video card are can also have a dramatic effect on overall speed. If your video card is from the Dark Ages and your hard drive is slower than your old stereo's 33 1/3 RPM turntable, loading your PC with 64MB isn't going to do an awful lot for you.

"OK, so what kinds of things will I notice as I add RAM to my system?"

That's a fair question. To answer it, I'll unscientifically compare three systems I use on a regular basis. Each runs OS/2 Warp with different amounts of RAM. The lineup:

My Business Notebook:
IBM ThinkPad 360CSE
Intel 80486/50 Processor

My Work Desktop Machine:
Gateway 2000 4DX2-66V
Intel 80486/66 Processor

The Family Home Computer:
Packard Bell Legend 100CD
Intel Pentium/66 Processor

I use each of these machines for different tasks, but all of them run similar software packages. All three use HPFS exclusively. The two desktop machines run video at 1024x768 resolution with 256 colors while the notebook runs 640x480 with 256 colors (the maximum available for the notebook). All three systems run a TCP/IP package. My notebook and home machine use the Internet Access Kit (IAK) while my work machine runs IBM TCP/IP for OS/2 with most of the available trimmings (NFS, X-Windows Server, etc.) and the latest patches. The NFS client and server functions are used regularly with other computers on a LAN. This PC is also equipped with the latest NetWare Client for OS/2 and attaches three NetWare servers and two network print queues.

In this unscientific test, what I looked for was speed of loading OS/2 and Windows applications (separate, seamless Win-OS/2 sessions for the Windows applications), overall responsiveness of the WorkPlace Shell (opening & closing folders and switching between programs), how much disk swapping goes on, and of course, the size of the swap file. My reason for using separate, seamless Win-OS/2 sessions for Windows applications is they require more system resources this way than when running them in a single session. I set the CONFIG.SYS files on each PC to the defaults first supplied by Warp's installation program. The overall results were interesting.

Even though it has the most RAM (32MB), my work machine also has the heaviest application load. The Window List routinely shows 12 separate programs running in the background taking care of various tasks this computer is responsible for handling every day. Add to this all of the background processes that don't show up in the Window List and you have a very busy system. This is all before I start doing my regular work! The swap file for this machine usually hovers around 12MB in size. Overall, WorkPlace Shell (WPS) responsiveness for this PC is the fastest of the three. Opening folders with only a few objects in them for the first time causes the traditional small amount of disk access found in Warp. Once opened, closing and then reopening the folders is much faster as Warp caches the contents of recently opened folders.

My work machine comes in second, however, in speed of loading and executing OS/2 and Windows applications. While there are no unusual amounts of disk swapping going on, this machine just can't keep up with my home computer when it comes to raw processor speed. This should be no surprise to those who switch between similarly equipped 486 and Pentium systems. Before I upgraded it, my home computer originally had 8MB of RAM. When I tried it with this amount, it was slower in almost every respect than my work machine despite the faster processor. It's often said that a 486/66 with 16MB of RAM can outperform a Pentium with 8MB - even though both systems will cost about the same amount of money. My unscientific observations definitely support this claim. If you are considering a new computer purchase on a limited budget, this is something to keep in mind.

I've already stated that my home machine is the fastest at application loading and execution. Ironically, it came in second in overall WPS responsiveness. I believe this may be more related to different system settings and a faster drive in my work machine than to RAM. My home computer's hard drive often appears to think for a split second before files are accessed. There is no such hesitation in my work system. I also have those annoying system sounds enabled on my home machine because my oldest daughter likes them. That results in this machine having more to do (loading & playing sounds) when you're navigating the shell. Otherwise, both systems feel similar in responsiveness and seem to have more than enough RAM for caching the contents of recently opened folders. Again, once an application is running, my home computer is faster. The swap file on my home computer starts at 2MB and rarely exceeds 8MB even under the heaviest loads it sees.

My notebook has the slowest processor and the least amount of RAM (12MB) of the three. It also winds up a distant third in performance to the other two. A typical workload on my notebook is almost identical to that of my home machine without the system sounds. Keep in mind my notebook has only half the RAM of my home computer. I quickly learned to never run more than three applications on my notebook at a time (two if one is a Windows application) unless I'm willing to accept very slow performance. After bootup has completed, the swap file hovers around 10-11MB and grows from there. A single Windows application will immediately increase the swap size to 13MB.

Without any applications loaded, WPS responsiveness is sluggish compared to the other systems, but is otherwise still within my own realm of acceptability. Load one Windows application and forget about responsiveness. Folders can take as long as 30 seconds to open or close, and switching to and from the Windows application becomes a major event. It's almost better to just exit the application and restart it when you need it again. Almost, but not quite. OS/2 applications, on the other hand, are less stressful, unless they are old or poorly optimized like the old version of Lotus AmiPro for OS/2, which is almost legendary for being rather piggish on performance.

"Speaking of Windows applications, how much more RAM do I need to make my PC run with the same snap as it does now with Windows 3.1 or Windows 95?"

This is a little tougher to answer for one platform and easy for the other. For Windows 3.1, I use what I call the 2MB rule. If you want to get roughly the same level of "snap" with Warp you now have with Windows 3.1, add 2MB. To put it another way, Warp in 6MB is about like Windows 3.1 in 4MB, Warp in 8MB is about like Windows 3.1 in 6MB, etc. This applies mainly to native applications. Windows applications running in separate Win-OS/2 sessions under Warp will obviously need more RAM. Again, this is because separate sessions require more resources. As you approach 16MB, this rule starts to break down (diminishing returns again) and Warp can actually wind up faster at some things. Keep in mind that, because Warp often has to access the hard drive when a folder is opened to do things like getting icons and object information, it will always feel a little slower. The WorkPlace Shell (PMSHELL.EXE) also does a lot more than Windows 3.1's Program Manager (PROGMAN.EXE), compounding the effects of feeling slower. Finally, remember that Warp and Windows 3.1 handle memory using very different methods. It will never be a true apples to apples comparison.

With Windows 95, I use the 0MB RAM rule. Similar scenario, different number. In fact, one can argue that, when running applications native to each OS, Warp is probably a little faster in systems with more than about 8MB. Because Windows 95, like Warp, tends to read the disk when opening folders, the advantage Windows 3.1 has is lost.

So what's the bottom line? I see it this way. If you're an average user running Warp, adding RAM to your system will definitely speed things up for you until you reach the 16MB range. After that, you should probably look at other things like faster video cards, hard drives or processors if you want more punch. On the other hand, if you regularly run memory intensive or more than several applications at the same time, going to as much as 32MB of RAM or more before looking at the other performance factors is probably the way to go. You'll definitely fall into this category if you run things like VisualAge C++, lots of big multimedia applications, do lots of heavy duty networking, or regularly handle huge graphic files. Ironically, if you can't let go of running more than a few Windows applications at the same time, you might also fit in the more RAM category.

Just remember, what's fast enough for one person might not be for another. In the final analysis, after you get safely past IBM's recommended minimums, how much RAM you really need is still subject to some interpretation.

editor's note: You can actually get a great deal on 16MB of RAM. The reason is that one 16MB chip costs less to produce than two 8MB chips. You should be able to get the 16MB chip for only one and a half times the price of an 8MB chip - not double! That means if memory goes for around $350/8MB in you area (as it does here), instead of $700 for a 16MB chip, you'll probably pay around $600. Of course these prices are only examples and change by the day.

Chris Williams has been actively involved with OS/2 systems for the past six years. A former IBM employee, OS/2 Ambassador, and long time member of Team OS/2, he is currently a PC and network specialist for Perot Systems Corporation.

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