[TUHS] The evolution of Unix facilities and architecture

Clem Cole clemc at ccc.com
Sat May 13 01:46:08 AEST 2017


I just did a small amount of hunting.  The oldest printed USENIX Proceeding
seems to be 1983 [which was the one Rob gave 'cat -v considered harmful' -
although only the abstract is in it].

George did the ordered writes work earlier as I was still at Tektronix,
because I remember getting a tape from him a putting the changes into our
V7 system.

If we hunt around for a 'Purdue-EE' distribution circa '79-'81 we should be
able to find it.  BTW: as a piece of History for Diomidis on that same tape
is fix for one of the first '0-day' UNIX exploits I can remember.  I'll see
if I can find it and identify it for you.   That would be a good piece of
history to call out.

The story is this ...

George was very upset when he found it.  But this was during the time when
UNIX was fighting a bit for it's life in the press as not being a 'real'
OS.   DEC and IBM making claims that it was a toy, *etc*.   So most of the
the hacker community took it pretty seriously.   It is funny, today we
would react in the opposite manner.,  But, there was a big 'hush-hush'
meeting at a Summer USENIX that was very exclusive to be invited too.    We
were in a private conference room, the door was locked etc.   I remember
that Dennis was there, Joy was there. Ron's old friend Mike must have been
in it.  I think a couple of the Rand folks.   Anyway - it was an issue with
profile(2) -- surprise, surprise.   Pretty easy fix.   We all took the code
back and promised to get patches out ASAP and not tell any one about it.

Clem

On Fri, May 12, 2017 at 11:18 AM, Clem Cole <clemc at ccc.com> wrote:

> I should have said -- it was not hypothetical -- George implemented it
> and published the code and we all picked it up,
>
> On Fri, May 12, 2017 at 11:17 AM, Clem Cole <clemc at ccc.com> wrote:
>
>> George Gobble of Purdue did the FS work to V7/4.1 to fix the FS
>> corruption issues.   That was taken back by Kirk (wnj) and incorporated in
>> 4.1A.    It may have been before USENIX was creating proceedings.   I'll
>> have to look on my shelf at home or maybe ask George.
>>
>> Clem
>>
>> On Fri, May 12, 2017 at 11:12 AM, Noel Chiappa <jnc at mercury.lcs.mit.edu>
>> wrote:
>>
>>>     > From: "Ron Natalie"
>>>
>>>     > Ordered writes go back to the original BSD fast file system, no?
>>> I seem
>>>     > to recall that when we switched from our V6/V7 disks, the
>>> filesystem got
>>>     > a lot more stable in crashes.
>>>
>>> I had a vague memory of reading about that, so I looked in the canonical
>>> FFS
>>> paper (McKusick et al, "A Fast File System for UNIX" [1984)]) but found
>>> no
>>> mention of it.
>>>
>>> I did find a paper about 'fsck' (McKusick, Kowalski, "Fsck: The UNIX File
>>> System Check Program") which talks (in Section 2.5. "Updates to the file
>>> system") about how "problem[s] with asynchronous inode updates can be
>>> avoided
>>> by doing all inode deallocations synchronously", but it's not clear if
>>> they're
>>> talking about something that was actually done, or just saying
>>> (hypothetically) that that's how one would fix it.
>>>
>>> Is is possible that the changes to the file system (e.g. the way free
>>> blocks
>>> were kept) made it more crash-proof?
>>>
>>>      Noel
>>>
>>>
>>
>
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