[fpc-devel] On a port of Free Pascal to the IBM 370

Mark Morgan Lloyd markMLl.fpc-devel at telemetry.co.uk
Thu Jan 19 20:09:45 CET 2012

Mark Morgan Lloyd wrote:

>> I think we need a reality check from Paul here, in case EBCDIC 
>> operation is mandated only by the emulator he was planning to use 
>> (whether I think his choice is good is irrelevant- lets try to get 
>> things like character set resolved before it causes any more sound and 
>> fury).

> I see MUSIC/SP described as "unix-like", but I don't know whether it is 
> sufficiently close to industry norms to run standard tools such as make, 
> and even if the compiler is intended to be PC-hosted I think that would 
> be unfortunate. MUSIC/SP running on Sim390 should have networking etc., 
> but I for one have reservations about an initial port to an OS that 
> might turn out to be significantly removed from POSIX etc. If I have 
> time I might have a bit more info on this later, as well as on the 
> character set issue.

MUSIC/SP internal character set appears to be EBCDIC, there are specific 
library functions for converting between this and ASCII with the latter 
described as for use on the Internet. However, this is a feature either 
of MUSIC/SP or of older mainframes, Linux running on Hercules is 
definitely ASCII:

$ xxd hello.p
0000000: 5052 4f47 5241 4d20 4865 6c6c 6f3b 0a0a  PROGRAM Hello;..
0000010: 4245 4749 4e0a 2020 5772 6974 6528 2748  BEGIN.  Write('H
0000020: 656c 6c6f 2c20 2729 3b0a 2020 5772 6974  ello, ');.  Writ
0000030: 654c 6e28 2757 6f72 6c64 2127 290a 454e  eLn('World!').EN
0000040: 442e 0a0a                                D...

> One important point, and I don't much like raising this, is that it 
> turns out that the principal maintainer of both MUSIC/SP (through his 
> work at McGill) and Sim390 died in 2008. I agree with Paul that a 
> mainframe port is worth attempting, but I've got reservations about his 
> choice of target hardware and OS unless he can make a case that there is 
> a significant number of S/370 and older (i.e. without inline operands) 
> S/390 still in the field.

Mark Morgan Lloyd
markMLl .AT. telemetry.co .DOT. uk

[Opinions above are the author's, not those of his employers or colleagues]

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