Path: utzoo!attcan!uunet!wuarchive!usc!apple!agate!ucbvax!mtxinu!sybase!binky!tim
From: tim@binky.sybase.com (Tim Wood)
Newsgroups: comp.databases
Subject: Re: Client/Server processes and implementations
Keywords: Client Server Processes
Message-ID: <7208@sybase.sybase.com>
Date: 24 Nov 89 20:42:51 GMT
References: <7114@sybase.sybase.com> <6895@sybase.sybase.com> <2184@kodak.UUCP> <375@xyzzy.UUCP> <510@xyzzy.UUCP> <936@anasaz.UUCP>
Sender: news@sybase.sybase.com
Reply-To: tim@binky.UUCP (Tim Wood)
Organization: Sybase, Inc.
Lines: 28

In article <936@anasaz.UUCP> john@anasaz.UUCP (John Moore) writes:
> ... However, if
>Unix is to be used seriously as a database server, ...
>... you need better I/O system, which has:
>asynchronous I/O, ordered I/O (FIFO disk I/O on request), and
>disk mirroring. Sybase has dealt with this by writing their own
>device driver. Unfortunately, this has limited their portability.

I'd like to clarify: on Sun platforms, users licence,via MtXinu, a
version of SunOS 3.x which we modified to support async I/O to raw
disks.  So the user would actually install a different version of
SunOS.  This was our only choice at the time to get the throughput
advance of async I/O on Sun at the time (and avoid using the UNIX file
system and its attendant inability to verify I/O completion).

Now that SunOS 4.x has this feature, Sybase 4.0 supports their 
implementation & the Pyramid implementation (I just looked at the
release code :-).  On VMS (which has always offered async I/O),
we have always taken advantage of the feature.

Sybase 4.0 has its own (portable) mirrored-disk facility and solves
the ordered-write problem independently of the OS (which is all I 
can say about it :-).

Sybase, Inc. / 6475 Christie Ave. / Emeryville, CA / 94608	  415-596-3500
tim@sybase.com          {pacbell,pyramid,sun,{uunet,ucbvax}!mtxinu}!sybase!tim
		This message is solely my personal opinion.
		It is not a representation of Sybase, Inc.  OK.