From owner-freebsd-small  Wed Oct  7 11:35:17 1998
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From: Bill/Carolyn Pechter <pechter@shell.monmouth.com>
Message-Id: <199810071834.OAA03528@shell.monmouth.com>
Subject: Re: Flash and Configuration Ideas [Was: Re: New microdrives from IBM]
To: petrilli@amber.org (Christopher G. Petrilli)
Date: Wed, 7 Oct 1998 14:34:19 -0400 (EDT)
Cc: freebsd-small@FreeBSD.ORG
In-Reply-To: <19981007133806.21614@amber.org> from "Christopher G. Petrilli" at Oct 7, 98 01:38:06 pm
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> 
> On Wed, Oct 07, 1998 at 07:31:03PM +0200, Andrzej Bialecki wrote:
> > On Wed, 7 Oct 1998, Christopher G. Petrilli wrote:
> > 
> > > I think it's extreemly important to focus on a GOOD flash file
> > > system---I'd settle for something a'la RT-11 and contiguous
> > > files---that doesn't have huge impact on flash re-write lifetimes.  
> > 
> > Hmmm.. What's an RT-11?
> 
> Oh dear, I date myself :-)  RT-11 was an OS from DEC in the 70s and 80s
> that ran on PDP-11s and was used for real-time systems.  I think at one
> point or another, about half the planet ran on it ;-)
> 
> The file system was very simple, and didn't have directory structures,
> which was fine for the time, since RL02 disk packs weren't very big :-)
> Basically, it required that all files be contiguous (and if I recall,
> you couldn't append, so you sized it right up front), and if there
> wasn't enough contiguouos space available for your file (even if there
> was enough space overall) then you couldn't write it.  On occasion you
> would compact the drive (a deliberate process) and recover space.

I believe you could append as long as you didn't hit the contiguous
block problem.  If there was unused block space behind your file you could
extend it.  If not...you had to compress the file first or write it to a new
series of blocks that could hold the entire file.

(Recovering lost files was trivial, you just created a file where the old
one was and it's data was back... kind of like CP/M and MS-DOS unerasure.)

Bill
(old RT11 hacker...)

+---------------------------------------------------------------------------+
| Bill and/or Carolyn Pechter    |        pechter@shell.monmouth.com        |
|   Bill Gates is a Persian cat and a monocle away from being a villain in  |
|  a James Bond movie              -- Dennis Miller                         | 
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