Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!cmcl2!rna!dan
From: dan@rna.UUCP (Dan Ts'o)
Newsgroups: comp.periphs
Subject: Re: WORMs acting like R/W disks...
Message-ID: <683@rna.UUCP>
Date: 30 Jun 89 23:31:35 GMT
References: <680@rna.UUCP> <191@arnor.UUCP>
Reply-To: dan@rna.UUCP (Dan Ts'o)
Organization: Rockefeller University Neurobiology
Lines: 23

In article <191@arnor.UUCP> uri@arnor.UUCP (Uri Blumenthal) writes:
>From article <680@rna.UUCP>, by dan@rna.UUCP (Dan Ts'o):
>> ......makes the WORM emulate a read/write
> Well, maybe I'm not that smart, but how the hell can you emulate read/write
> device on Write-Once-Read-Many? As I understand, it will be either TERRIBLY
> non-effective (like zillions of bytes be eaten as garbage), or it will not
> work at all (:-)! 
> So to use it as a source archive (with modifications once in every 100 years),
> you probably can (if you're leaving at least 35% of WORM space free for those
> games). But that's all!

	Well, of course it wouldn't be very good for putting your
/usr/spool/news filesystem on. But /usr/src, probably pretty good. The point
is that many of us have storage applications requiring random, moderately fast
access (scratch Exabyte), large capacity and not too many changes (images,
for example, or school records), but have not been able to use WORMS
effectively because existing OS's and device drivers and filesystems require
read-write semantics. Special software drivers must be written to allow
transparent access to WORMS from UNIX, MSDOS, VMS, etc. However this OCU
box eliminates the need for special software by putting all those functions
and workarounds in "hardware" (host and OS independent hardware).
	But the write-once limitation isn't going to go away, not entirely.
Sometimes you want 800Mb of archival info on a $100 cartridge.