steve smithers wrote:
rvmart...@ntlworld.com wrote on Thu, 2 Feb 2012 16:28:29 +0000 (GMT)
..
"Write once, compile anywhere" isn't that the motto? I'm not trying to suggest
anything to break this model, but when I compile my code on the mainframe, I
would expect stuff like if ch in['A'..'Z'] to be EBCDIC based.
That's reasonable, but is of course an RTL issue- or if it's not an RTL
issue today I suspect it will be at the end of this port :-) However as
Tomas points out the compiler will also have internal lists of reserved
words and (pseudo-) procedures, and it might be that at present they
assume ASCII collation order.
Mark Morgan Lloyd <markmll.fpc-de...@telemetry.co.uk wrote on Thu, 02 Feb 2012
17:27:51 +0000
I'd only expect the version control system to contain textfiles. Or are
you saying that some IBM operating systems support files which contain
both text and data (I'm aware of the Mac's OS and obviously OS/2 doing
this, both of which FPC supports).
I wasn't really talking about source files. I was talking about I/O in
general. Translating a text file on the fly is possible, assuming you
can identify it as such. But what about a structured file that contains
mixed binary and string info. Integers need to converted from little to
big endian, strings from ASCII to EBCDIC, floating point from PC to mainframe
formats, files may contain internal pointers to other info, again it needs
to be converted. Doing all this automagically in the RTL isn't an exercise
in coding it's clairvoyance. And yes, MVS supports mixed binary and string
data in a file, doesn't every operating system?
Yes, but some operating systems also support there being multiple forks
(or some comparable term) of a file, so that (for example) an executable
file contains both binary code and *separate* resource/message data,
both of which can be read sequentially starting from zero. Think two
columns in a database, both blobs.
Just trust me then. PC doctrine has it that anybody can write a
compiler, but we're aware of the fact that other architectures might do
things differently.
Anyone can write whatever they want on the mainframe too. All the tools
required are provided. What you do with it has nothing to do with architecture,
it's to do with security. If you were a user on a Linux system, one amongst
50 others, one without root access, you would find yourself constrained about
what you and your compiler could do. At least I hope you would.
Yes and no. An unprivileged user on Linux can compile a kernel, or can
even build a compiler which is then used to build a kernel, and the end
product would be bootable or executable. The only thing he can't do is
tell the system-wide boot manager to load the kernel at the next
startup, or put the compiler where it is executed as the system default.
Some operating systems require a special blessing or signing stage in
those cases. If IBM OS and its brethren don't, then it makes life a bit
easier.
No, but having an accessible operating system for testing is, and it
would end up being extremely inconvenient if that operating system
didn't support standard networking so that- at the very least- test code
code could be got onto it and copies of error messages got off. I don't
think the other developers would be happy if told they had to use
(something equivalent to) Kermit :-)
Hercules provides terminal access to a TCP/IP client, both in 3270 terminal
mode and for file transfer. As far as I know Kermit is not available
Hercules certainly does. MUSIC/SP (which was what was originally
suggested as a target operating system) only provided TCP/IP if run on
VM, or on Sim/390 which is Windows-only.
--
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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