Session S930 - OS/2 Technical Perspective

SHARE 70
February 29 - March 4, 1988

This was the first of three sessions that I went to that discussed OS/2, the newest, greatest and largest operating system for PCs. During the day the lectures were punctuated by live demos in the back of the room where two PS2/60 machines were linked to each other and to an IBM mainframe in Austin. One of the PS2s had 5 megabytes of memory and the other had 7 megabytes. The PCs had 10 simultaneous mainframe sessions going, and maybe 5 other programs running in windows on the screen, all simultaneously. It was pretty impressive.

(The software they brought was early copy; during the course of their demonstrations, they had the occasional opportunity to demonstrate the IPL procedure. And so it goes.)

OS/2 Extended Edition (EE) includes a communications manager, a database manager, and LAN support. It is SAA compliant, meaning that they support a single userid, a single screen, and a single interface.

OS/2 likes memory. IBM said that the average program size for PCs these days runs from 300-500K bytes. This will get bigger. OS/2 Standard Edition (SE) required 5.4 to 6.4 megabytes of disk space and 1.5 to 3.8 megabytes of memory to run! The amount of memory required depends on whether you run the spooler, whether you have DOS compatibility and so on.

The token-ring LAN that IBM supports runs at 4 megabits per second, and IBM says "we're going higher". Film at eleven, I suppose.

The OS/2 Communications Manager is a modular piece (an add-on, if you will), and supports concurrent X.25, SYNC and ASYNC protocols. LU 6.2 is the vehicle for all future communications. They will support LU 2.0 (3270) protocols "for migration and coexistence". IBM observed that in 1988, maybe 8% of computer time (PCs) is used for communication. In 1992 they project that communications will take up 90% of a PC's time. Connectivity is vital to the success of OS/2.

OS/2 provides varying degrees of I/O overlap, depending on whether you are running it on an AT or a PS2. The MCA bus on the PS2 allows overlapped I/O along with CPU activity. On the AT, OS/2 overlaps disk seeks with CPU activity (PC-DOS doesn't even do this much). This implies that disk-intensive programs under PC-DOS will improve under OS/2 due to the seek overlap and disk caching performed by the operating system.


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