John This discussion reminds me of the deliberate title I created for a "field-developed program" I wrote which enabled an English Electric System 4 assembler program to be compiled and run on OS (one of MFT or MVT or whatever immediately followed).
The System 4 machine architecture was the same as the 360[1] but the operating system, the System 4 DOS, was a bit like IBM DOS (now VSE) but different. Customer programs tended to be written in Assembler because the COBOL compiler was, at the time, the early '70s, rather new. I tackled the problem by replacing all the System 4 DOS macros with my own and arranged to map them to OS functions. I was sensitive to smart-**** programmers who may have used relative addressing around macros so the code I generated with my macros had to use the same number of bytes. For macros wrapped around an SVC, I created a pseudo-SVC, X"0B", and handled the function in the "program check" routine - I forget the name now. This may not have been the cleverest technique but it got the job done and I didn't expect "SVC macros" to be called in the main program loop. I/O macros (except OPEN/CLOSE) were wrapped around a BALR, of course, rather than an SVC. The System 4 manuals implied being able to read blocked variable length records on tape backwards so my version of the tape I/O had to handle that. In fact, I doubt whether System 4 really did support blocked variable length records on tape backwards. OS also appears to have this support but barfs (or barfed - maybe it's there now) if you try it. The package was given the long title "System Interface Modules for System 4" which abbreviated to "SIM/4" (sort-of) and so had the implied quality of being a "simulator". According to definition 3a in your post, it looks as if it was really an "emulator". If this product was ever sold, nobody ever bothered to let me know - so either it was never sold or it worked perfectly and the documentation was clear and complete. I used it only a limited number of times in demonstration mode, once each in England, Scotland[2] and Bulgaria. I also discussed its possible use in detail to two prospects in Moravia, the eastern part of the Czech Republic. (The geography illustrates two of the principle marketing areas for ICL.) Thus the value of the "simulator" was in supporting marketing efforts: "If it's so easy to "simulate/emulate" on IBM machines, it must be easy to convert properly." [1] English Electric[3] got the System 4 from RCA where it went under the name "Spectre". [2] The local authority of the capital city to whose folk I presented three punched cards together with the proof of success printout from the supplied production programs. The cards represented my having to compensate manually for some sort of minor syntax difference in the treatment of continuation punches if I remember well. [3] A company, specifically English Electric Computers, which merged with ICT to become ICL which then became part of Fujitsu. Chris Mason ----- Original Message ----- From: "Chase, John" <[EMAIL PROTECTED]> Newsgroups: bit.listserv.ibm-main To: <[email protected]> Sent: Tuesday, 12 December, 2006 1:58 PM Subject: Re: IBM sues maker of Intel-based Mainframe clones > > -----Original Message----- > > From: IBM Mainframe Discussion List On Behalf Of John P Baker > > > > If I understand the filing, I believe that the difference is > > that both FLEX-ES and Hercules are in fact "instruction > > simulators", whereas PSI was producing an "instruction emulator". > > From http://www.dictionary.com: > > Emulate [emulator]: > > 3. Computers. a. to imitate (a particular computer system) by using a > software system, often including a microprogram or another computer that > enables it to do the same work, run the same programs, etc., as the > first. > b. to replace (software) with hardware to perform the same task. > > Simulator: > > 2. a machine for simulating certain environmental and other conditions > for purposes of training or experimentation: a flight simulator. > > Not a whole lot of difference there.... > > -jc- ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
