I ran TOS/360 assemblies on a S/360 model 30 with 16K of storage, so the whole assembler fit in 16K. In fact, it had to fit in about 10K, which was all that was left after the approximately 6K self-loader loaded in the "supervisor" from tape and then loaded the assembler from tape. TOS/360 and DOS/360 both made extensive use of "transient" routines, which was TOS/DOS terminology for overlays.
A really scary phenomenon was when the TOS (Tape Operating System) assembler had been assembling for a while and then it encountered a temporary read or write error on one of its temporary work files which, of course, were allocated on tape. The SYSRES tape would rewind to find the $$A transient that processed I/O errors, then the tape would forward space back to where the error block was, retry the I/O a few times, and then resume normal processing after the tape block had finally been read or written without a temporary error. Bill Fairchild Rocket Software -----Original Message----- From: IBM Mainframe Discussion List [mailto:ibm-m...@bama.ua.edu] On Behalf Of Shmuel Metz (Seymour J.) Sent: Sunday, August 01, 2010 6:31 AM To: IBM-MAIN@bama.ua.edu Subject: Re: History of Hard-coded Offsets (Was: TSSO problems) In <8924.40203...@web82202.mail.mud.yahoo.com>, on 07/20/2010 at 08:08 AM, Lloyd Fuller <leful...@sbcglobal.net> said: >Remember: there used to be several levels of assembler: D, E, and F >as well as H. D and E in particular had lots of restrictions on >what MACROs and COPYs could do because of lack of memory. I believe >D would run in a 64K real machine and E required 96K machine. The DOS/360 and TOS/360 Assembler (D) had a 16 KiB design level and, while it exceeded that, I don't believe that it exceeded it by that much. Similarly, the OS/360 Assembler (E) and (F) had 32KiB and 64KiB design points; again, they didn't exceed those sizes by that much. Perhaps you meant that Assembler (F) required a 96 KiB machine. >I believe HLASM is based on the H level assembler with lots of >changes. Soem of which had been developed at SLAC. -- Shmuel (Seymour J.) Metz, SysProg and JOAT ISO position; see <http://patriot.net/~shmuel/resume/brief.html> We don't care. We don't have to care, we're Congress. (S877: The Shut up and Eat Your spam act of 2003) ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
