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From: henry@utzoo.UUCP (Henry Spencer)
Newsgroups: comp.os.minix
Subject: Re: First MINIX source question
Message-ID: <7602@utzoo.UUCP>
Date: Sat, 31-Jan-87 23:26:05 EST
Article-I.D.: utzoo.7602
Posted: Sat Jan 31 23:26:05 1987
Date-Received: Sat, 31-Jan-87 23:26:05 EST
References: <125@ems.UUCP>
Organization: U of Toronto Zoology
Lines: 25

> h/callnr.h is missing the following system call numbers: 11, 26, 31, 32,
> 34, 35, 38-40, 44, 45, 49-53, and 55-58.  Is this due to a desire to keep
> in line with Version 7 UNIX, or are these 'slots' reserved for future
> expansion?  Is there some historical reason for this, or was it just due to
> editing, etc?

It's probably V7 compatibility.  I don't know why he bothers, since I can't
think of any code that knows these numbers which isn't hopelessly hardware-
dependent.

11 is exec, obsoleted by exece.  26 is ptrace, which only debuggers use,
and there isn't one in MINIX yet.  31 and 32 are stty and gtty, long since
superseded by ioctl.  34 is nice, which would actually be useful, but might
take a fancier scheduler.  35 is ftime (yields time, fraction-of-second 
time, timezone, daylight-saving indicator); this omission surprises me. 
38-40 are unused in V7.  44 is prof, which only profilers ever use.  45
is unused, as are 49 and 50.  51 is acct, used only by system accounting
packages.  52 is phys, which maps physical address space into the process's
address space -- unimplementable on an 8088.  53 is lock, which locks the
process in core, preventing swapping, which is redundant since MINIX doesn't
swap.  55 is unused.  56 is mpxchan, which you *don't* want to know about
and neither does Andy.  57 and 58 are unused.
-- 
Legalize			Henry Spencer @ U of Toronto Zoology
freedom!			{allegra,ihnp4,decvax,pyramid}!utzoo!henry