Tonal languages are real fun. I'm living and working in Bangkok,
Thailand and slightly tone deaf am still struggling.
Which reminds me, regarding binary there are 10 types of people, those
who understand and those who don't :-)
Cheers,
rudi
Noel:
Instead, you have to modify the arguments so that the re-tried call takes up
where it left off - in the example above, tries to read 5 characters, starting
5 bytes into the buffer). The hard part is that the return value (of the
number of characters actually read) has to count the 5 already read! Without
the proper design of the system call interface, this can be hard - how does
the system distinguish between the _first_ attempt at a system call (in which
the 'already done' …
[View More]count is 0), and a _later_ attempt? If the user passes in
the 'already done' count, it's pretty straightforward - otherwise, not so
much!
====
Sometime in the latter days of the Research system (somewhere
between when the 9/e and 10/e manuals were published), I had
an inspiration about that, and changed things as follows:
When a system call like read is interrupted by a signal:
-- If no characters have been copied into the user's
buffer yet, return -1 and set errno to EINTR (as would
always have been done in Heritage UNIX).
-- If some data has already been copied out, return the
number of characters copied.
So no data would be lost. Programs that wanted to keep
reading into the same buffer (presumably until a certain
terminator character is encountered or the buffer is full
or EOF) would have to loop, but a program that didn't loop
in that case was broken anyway: it probably wouldn't work
right were its input coming from a pipe or a network connection.
I don't remember any programs breaking when I made that change,
but since it's approaching 30 years since I did it, I don't
know whether I can trust my memory. Others on this list may
have clearer memories.
All this was a reaction to the messy (both in semantics and
in implementation) compromise that had come from BSD, to
have separate `restart the system call' and `interrupt the
system call' states. I could see why they did it, but was
never satisfied with the result. If only I'd had my inspiration
some years earlier, when there was a chance of it getting out
into the real world and influencing POSIX and so on. Oh, well.
Norman Wilson
Toronto ON
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>On Tue, 21 Feb 2017 19:08:33 -0800 Cory Smelosky wrote:
>
>>On Tue, Feb 21, 2017, at 17:22, Rudi Blom wrote:
>> Probably my (misplaced?) sense of humour, but I can't help it.
>>
>> After reading all comment I feel I have to mention I had a look at
>> freeDOS :-).
>>
>> Cheers,
>> rudi
>
>Do I need to pull out TOPS-10 filesystem code now, too? ;)
In 1967 I was 12 and probably had barely discovered ScienceFiction
novel and computers.
…
[View More]Just quickly downloaded a TOPS-10 OS Commands Manual (from 1988) but
no mention of the Level-D filesystem
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Probably my (misplaced?) sense of humour, but I can't help it.
After reading all comment I feel I have to mention I had a look at freeDOS :-)
Cheers,
rudi
All, after getting your feedback, I've reorganised the Unix Archive at
http://www.tuhs.org/Archive/
I'm sure there will be some rough edges, let me know if there is anything
glaringly obvious.
I'd certainly like a few helpers to take over responsibility for specific
sections, e.g. UCB, DEC.
Cheers all, Warren
P.S It will take a while for the mirrors to pick this up.
> 2) **Most** Operating systems do not support /dev/* based access to SCSI.
> This includes a POSIX certified system like Mac OS X.
>
> 3) **Most** Operating systems do not even support a file descriptor based
> interface to SCSI commands.
> This includes a POSIX certified system like Mac OS X.
Had Ken thought that way, Unix's universal byte-addressable file format
would never have happened; this mailing list would not exist; and we
all …
[View More]might still be fluent in dialects of JCL. dd was sufficient glue
to bridge the gap between Unix and **Most** Operating Systems.
Meanwhile everyday use of Unix was freed from the majority's folly.
Doug
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> From: Larry McVoy
> The DOS file system, while stupid, was very robust in the face of
> crashes
I'm not sure it's so much the file system (in the sense of the on-disk
format), as how the system _used_ it (although I suppose one could consider
that part of the FS too).
The duplicated FAT, and the way file sectors are linked using it, is I suppose
a little more robust than other designs (e.g. the way early Unixes did it,
with indirect blocks and free lists), but I think a …
[View More]lot of it must have been
that DOS wrote stuff out quickly (as opposed to e.g. the delayed writes on
early Unix FS's, etc). That probably appoximated the write-ordering of more
designed-robust FS's.
Noel
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> From: Diomidis Spinelli
> Arguably, the same can also be claimed for the networking system calls.
Well, it depends on exactly what you mean by "networking system calls". If
you mean networking a la BSD, perhaps.
However, I can state (from personal experience :-) that the I/O architecture
circa V6/V7 was not very suitable for TCP/IP internetworking (with its
emphasis on an un-reliable network, and smart endpoints). The reason is that
such networking doesn't really fit well into …
[View More]the 'start one I/O operation and
then block the process until it completes' model.
Yes, if you have an application running on top of a reliable stream, you
might be able to coerce that into the 'uni-directional, blocking' I/O model
(if the reliable stream implementation is in, or routed through, the kernel),
but lots of other thing don't work so well. (Think, e.g. an interface with
asynchronous, un-predictable, RPC calls in both directions.)
Noel
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> Linus had the qualities of being a good programmer, a good architect,
> and a good manager. I've never seen all 3 in a person before or since.
No comment about Linus, but Vic Vyssotsky is my pick for the title.
He created the first dataflow language (in 1960!). He invented
bit-parallel flow analysis and put it into Fortran 2 years later.
He was one of the technical triumvirs for Multics. Ran several
big development groups at Bell Labs, and was 2 levels up from
the Unix team in …
[View More]Research. I could go on and on. What he
didn't do was publish; he got ahead on pure innate ability
and brilliant insight--a profound influence on almost all]
the original Unix crowd.
Doug
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I dont know if it's worth even trying to find and mirror pre 1993 ( IE when cheap CD-ROM mastering was possible) GNU software?
Things like binutils, gas, and GCC can be tremendously useful, along with binaries for long "dead" platforms?
I know that I've always been super thankful of the GNAT people for having some pre-compiled version of the ADA translator which would also include GCC. Sometimes having some kind of native toolset is a big positive, when you don't have anything, especially …
[View More]earlier versions that have issues cross or Canadian cross compiling.
--
Sent from my Android device with K-9 Mail. Please excuse my brevity.
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