Path: utzoo!mnetor!uunet!lll-winken!lll-lcc!ames!pasteur!ucbvax!bloom-beacon!think!ephraim
From: ephraim@think.COM (ephraim vishniac)
Newsgroups: comp.sys.mac
Subject: Re: dqDrvSiz
Message-ID: <17351@think.UUCP>
Date: 1 Mar 88 14:36:15 GMT
References: <978@ut-emx.UUCP>
Sender: usenet@think.UUCP
Reply-To: ephraim@vidar.think.com.UUCP (ephraim vishniac)
Organization: Thinking Machines Corporation, Cambridge, MA
Lines: 14
Keywords: large drive

In article <978@ut-emx.UUCP> rick@ut-emx.UUCP (Rick Watson) writes:
>Does anyone remember the extension made to the drive queue entry
>to allow drives with more than 65536 blocks?  It had something to do
>with putting the high-order bits somewhere else, but I can't remember where.

The high-order sixteen bits of the drive size were put in a word
following the low-order sixteen bits (that's backwards, by 68000
standards).  To distinguish drive queue elements which used this
extended format, the queue element type was changed from zero to one.

Ephraim Vishniac					  ephraim@think.com
Thinking Machines Corporation / 245 First Street / Cambridge, MA 02142-1214

     On two occasions I have been asked, "Pray, Mr. Babbage, if you put
     into the machine wrong figures, will the right answers come out?"