Hybrid Computertab machine data centers 801

rpl

DOS-VS is a different operating system than plain DOS. DOS was for System-360, DOS-VSE was for S-370 and later machines.

The S-360 was designed for multi-tasking. That is, while the CPU was waiting for an I-O operation to occur, it would be switched to another task and work on that.

Unit-record (punched card and printer) I-O was extremely slow. Running such jobs on the machine would leave the wait light on almost continuously since so few CPU cycles were required. Because the job was dependent on the speed of the card reader and printer, tape and disk work had to wait, too, as of course the CPU.

By spooling those jobs ahead of time, the CPU could read and print far faster to disk than to actual unit record devices. This allowed the jobs to go through much faster. (Remember too that while one job was running, cards would be read in for the next one and printing went on independently.)

In S-360 DOS, you needed a separate program "Power" and a partician for it. Our 1401 people weren't used to the idea and were amazed at the speed improvement.