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System 36

The IBM System/36 was a simple and popular small business computer system, first shipped in 1983. It had a 17-year product lifespan.

The first model of the S/36 was the 5360. Weighing in at 800 pounds, costing $100,000 and more, it was certainly no laptop, and on a good day it might have cranked up to 20 MHz. But in 1983, it was faster than any of the so-called "Personal Computers (PCs)" you could buy. The 5362 was a mere 150 pounds, and at $20,000, set the pace for corporate computing.

In the 1970s, the US Justice Department brought an antitrust lawsuit against IBM, claiming it was using unlawful practices to knock out competitors.

At this particular time in history, IBM was about to consolidate its entire line (S/370, 4300, S/38, S/34) into one "family" of computers, with the same ISAM database technology, programming languages, hardware architecture, etc. As soon as the lawsuit got rolling, IBM decided it would have *two* families -- the System/38 line, representing large companies and the future of the company, and the System/36 line, representing small companies and the company's settled, off-the-shelf, System/3/32/34 past.

And so it was that from Day One, the System/36 used virtually the same RPG II, SDA, OCL, and everything else that the System/34 used. It was object-code incompatible, and the screens (at 24x80) were twice the size, but very much similar. If the Justice Department decided to break up the company, IBM would have the ability to retreat just one step, and let go of the less-valuable S/36 community in favor of the S/38.

The S/36 was a small business computer. It had an 8-inch diskette drive, between one and four hard drives in sizes of 30 to 716 Mb, and memory from 256K up to 7MB. You could buy various tape drives as backup devices.

The S/36 environment, at its core, was the command-line, but, it was more friendly than the S/34 because of 100 or so "menus" that simplified the command process. An operator could type BLDLIBR MYLIB,100,30 to create a user program "library," or jump from one menu to another to find the description, "Create a user library," and fill in a simple form to accomplish the same goal.

RPG II was a far cry from RPG I, which was based on card readers, disk packs, and printouts, because it allowed access to "the WORKSTN file," which was the method used to make a language based on cards interact with a person sitting at a keyboard and looking at a monitor. A WORKSTN file was an output file, that is, it wrote to the monitor, and it was also an input file, because it accepted the user's keyboard input.

Command keys became RPG indicators KA-KY, and different on-screen forms were recognized by different invisible control characters hidden in the forms themselves. Most interesting of all, since you had to have a form on the screen in order to type, RPG II had to provide a way for the programmer to output to the file before input. Most of the succesful programmers I have known broke away from the combined-primary WORKSTN file to the combined-demand file, which had operation codes to read and write the display. There was even a way to code for multiple WORKSTNs... several people could sign on to the same copy of the same program in memory. The largest program size was 64k.

There were a couple of holdovers from the days of the System/32, the "Bionic Desk" of 1975, and these were the KEYBORD, CONSOLE, and DISPLAY files which provided unformatted access to the monitor and keyboard. A novel trick allowed S/36 programmers to use a KEYBORD file to accept commands from the procedure (the "system input file",) meaning that a program could be customized at run time without a recompilation.

// LOAD MYPROG // FILE NAME-INPUT // RUN THIS IS CUSTOM DATA SO IS THIS /* (means end of data)

What could you do with a System/36?

- You could connect 36 monitors and printers together. Everyone could access the system's hard drive or any printer.

- You had very good password security and resource security. You could easily control who accessed what program or file.

- Your devices could be as far as a mile from the system unit.

- With communications, you could dial into your System/36 from anywhere in the world and get a 9600 baud connection, which for the 1980s was really, really good. Ninety-six hundred baud is quick when you're not moving graphics, sounds, or big datafiles, just screen text.

- You could create databases of unlimited size. Well, not really "unlimited," because the largest 5360 with 4 hard drives in the extended cabinet was a whopping 1.453 gigs. But until 1995 that was a lot. If you don't use JPGs and MP3s, it's still a lot. The limit for record count was about 8 million records, and the most I ever used was 1 million. A million records is a *lot*. Modern-day programs like Microsoft Access and Excel start choking well before that. It's the fault of a thing we call the PC kernel.

The S/36 was "bulletproof." You turn it on and it worked. And worked. And worked. The original S/36 could run for 6 weeks or longer between restarts (IPLs.) At the end, we were running the systems for 6 months at a time, only shutting down to change the clock for Daylight Savings Time.

In the late 80s, IBM was no longer targeted by US Justice, and so IBM went forward with its vision, which it named the AS/400. The early model was very much like a powerful, cheap, downsized S/38 with a super database, and so was instantly popular among the 20,000 S/38 customers. But the 300,000 S/34 and S/36 customers lingered. IBM tried different things to get them to migrate, but people who paid $20k for their S/36 didn't want to pay $40k for the AS/400. In 1994, the Advanced 36 was released. Bargain priced as low as $7995, it was the machine that allowed S/36 folks to get modern, fast hardware while "staying 36."

Now, the AS/400 is great. It is the best database machine on the market today, bar none. But it was not all *that* much better than the S/36 used to be, other than much much faster and more complicated. It was very expensive to move from one machine to the other, rewrite programs, retrain personnel, etc. I never convinced one owner to quit their S/36 and go to AS/400, which is too bad, because, believe me, I would have been much better off if they did.

The Advanced 36 used an interesting feature allowing the operating system of the S/36, SSP, to be contained within AS/400's OS/400 as a "virtual machine," so it could be upgraded to a full-blown AS/400 for $15k.

What the AS/400 did not conquer of the S/36 world was swallowed up by the PC phenomena. MS-DOS and Windows are not nearly the database equal of SSP, but time and technology took their toll on a machine that basically hadn't changed much since 1983. And an entire generation of computer-savvy kids, teens, and adults didn't know the AS/400 from a hole in the ground, but everyone knows the PC.

By 2000, the Advanced 36 was withdrawn from marketing, and S/36s are disappearing rapidly in a marketplace geared to AS/400s and PCs. In a few years, they'll all be gone.

But, once upon a time, long, long ago, there was a computer that was fast enough, almost never crashed, had good security, and wouldn't play game disks your employee brings from home.



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