Mason McDuffie

 

I didn’t really like that job and in less than a year I found a better job working for Mason McDuffie, a large real-estate company in Berkeley.  In those days most real-estate offices would not have had a computer, but Mason McDuffie was larger than most.  They also had real-estate-related businesses, such as home-owners’ insurance and mortgage loans.  I worked on the loan servicing system. 

 

Mason McDuffie had a System/360 but it was a smaller model than the one I had used in the Army.  Because of its smaller size, and particularly its smaller memory it was unable to run OS/360.  IBM had conceived the System/360 line as an entire range of computers, from “small” to “large”.  (Neither of those adjectives seem to fit when compared to today’s computers:  Their largest system was less powerful than the laptop PC I’m writing this on;  their smallest computer on the other hand was larger than a refrigerator, making it several orders of magnitude larger than my palmtop.)    All of the computers in the series were to process the same machine language and run the same operating system.  They generally succeeded in the former.  There were a few models with various special features, but in general they all understood the same machine language, thanks to the use of microcode.

 

However, they were not so successful when it came to OS.  OS/360 turned out to require more memory than the maximum memory available for the smallest models.  And so they had to invent a second operating system for these machines which they called BOS (Basic Operating System). 

 

Another problem that BOS addressed was that some of these smaller systems were tape based—they didn’t have any disk storage.  So BOS had to “variants”:  “BOS Tape Variant” and “BOS Disk Variant”.  The former evolved into TOS (Tape Operating System) and the latter into DOS (Disk Operating System).  (This DOS is not to be confused with MS-DOS or PC-DOS which was the original operating system on IBM personal computers—that was a completely different system, written several years later.)

 

Anyway Mason McDuffie used DOS.  I had used OS in the Army, but the trade school I had attended in L.A. used DOS and that experience helped land me the job at Mason McDuffie. 

 

Before getting the programming job at Mason McDuffie, I had actually worked for them a couple of times on a temporary basis as a computer operator.  I remember the first time I showed up to work for them, the manager sat with me and said, “OK, first, power on the machine.”  I explained that I had actually never done that:  the computers I had worked on had been kept busy 24 hours a day and were never shut off.  I guess he accepted that, because he didn’t send me packing.