Re: [COFF] Other OSes?

On Sun, Jul 08, 2018 at 09:25:27PM -0600, Grant Taylor via COFF wrote: There were multiple OS's for the PDP-8 and PDP-15. What I used on the PDP-8/i was the 4k disk monitoring system, so named becasue it only required 4k of 12-bit wide core memory. The resident portion of the OS only required 128 12-bit words, loaded at octal 7600, at the top of the 4k memory. It could be bootstrapped by toggling in 4 (12-bit wide) instructions into the front console which had about 24 binary switches[1]. [1] https://www.youtube.com/watch?v=yUZrn7qTGcs The OS was distributed on paper tape, which was loaded by toggling in 18 instructions of the RIM loader, which was then to load the BIN loader from paper tape into core memory. The RIM loader was designed to be simple and easy to toggle into the console. (ROM? EPROM? We don't need no stink'in firmware in read-only memories!) The BIN loader could read in a more effoiciently packed data stored in punched paper tape. The BIN loader would then be used to load the disk builder program which would install the OS into the DF-32 (which stored 32k 12-bit words on a 12" platter). Later PDP-8's would run more a sophisticated OS, such as OS/8, which had a "Concise Command Language" (CCL) that was designed to be similar to the TOPS-10 system running on the PDP-10. OS/8 was a single-user system, though; no time-sharing! The PDP-15/30 that I used had a paper tape reader and four DECtape units. It ran a background-foreground monitor. The background system was what was used for normal program development. The foreground job had unconditional priority over the background job and was used for jobs such as real-time data acquisition. When the background/foreground OS was started, initially only the foreground teletype was active. If you didn't have any foreground job to execute, you'd start the "idle" program, which once started, would then cause the background teletype to come alive and print a command prompt. So it was a tad bit more sophisticated than the 4k disk monitor system. There have been times when I'll do something like this in a shell script: #!/bin/sh for i in file1 file2 file3 ; do ed $i << EOF /^$/ n s/^Obama/Trump/ w q EOF done This is a toy example, but hopefully it gets the point across. There are times when you don't want to use a stream editor, but instead want to send a series of editor commands to an editor like /bin/ed. I suspect that younger folks would probably use something else, perhaps perl, instead. - Ted