Path: utzoo!mnetor!uunet!husc6!think!ames!pasteur!ucbvax!hplabs!hp-pcd!hpcvlx!kam
From: kam@hpcvlx.HP.COM (Keith Marchington)
Newsgroups: comp.unix.wizards
Subject: Re: Jerry Pournelle on UNIX (From BYTE)
Message-ID: <1570001@hpcvlx.HP.COM>
Date: 22 Jan 88 21:29:21 GMT
References: <11194@brl-adm.ARPA>
Organization: Hewlett-Packard Co., Corvallis, OR, USA
Lines: 37


>In article <1410@sugar.UUCP> peter@sugar.UUCP (Peter da Silva) writes:
>>The HP Integral handled this by copying the ROM to RAM at boot time, and
>>keeping the file system in a RAM disk. It's also the first system I know of
>>in which the RAM disk is allocated and freed as needed (the second is the
>>Commodore Amiga).
>

Not really.  The Integral would create the file system in RAM disk at boot 
and then go out and look for all of the appropriate ROM 'disks' out in its
address space.  The address space was divided into 7M RAM, 1M I/O, and 8M ROM
if I remember correctly.  Any appropriate ROM disks were consolidated into
/rom.  The rest of the above info is essentially correct.

>Um, the read-only file system being discussed is over 500 megabytes; I doubt
>that it will fit in the RAM of many home computers.
>

Granted, such a file system would not fit into normal RAM.  But using the 
Integral scenario, such a thing would be quite possible.

>On the other hand, I could believe that interesting portions of it could be
>read into RAM (like the directory tree) so that lookups would be fast; this
>is one way to help alieviate the high seek time.
>

Exactly!

>(I didn't know that RAM: was ever freed; I thought that only VD0: and VDK:
>did that.....)
>-- 
>-- Greg Noel, NCR Rancho Bernardo   Greg.Noel@SanDiego.NCR.COM  or  greg@ncr-sd
>----------

Keith Marchington
Hewlett-Packard
Corvallis, Oregon