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From: steve@etn-rad.UUCP (Steve Childress)
Newsgroups: comp.sys.amiga
Subject: Re: hard disk flaw problems
Message-ID: <310@etn-rad.UUCP>
Date: Fri, 27-Nov-87 20:37:42 EST
Article-I.D.: etn-rad.310
Posted: Fri Nov 27 20:37:42 1987
Date-Received: Mon, 30-Nov-87 01:32:05 EST
References: <1884@cadovax.UUCP> <2605@masscomp.UUCP> <1888@cadovax.UUCP>
Reply-To: steve@etn-rad.UUCP (Steve Childress)
Organization: Eaton Inc. IMSD, Westlake Village, CA
Lines: 33
Keywords: hard disk format flaws

In article <1888@cadovax.UUCP> kaz@cadovax.UUCP (Kerry Zimmerman) writes:
>In article <2605@masscomp.UUCP> rad@masscomp.UUCP (Bob Doolittle) writes:
>>In article <1884@cadovax.UUCP> kaz@cadovax.UUCP (Kerry Zimmerman) writes:
>>
>>I have heard from my local service rep that you can't tell the 2090
>>about a disk with greater than 50Mb capacity :-(.  
>>
>
>
>I don't think if there is such a limit, that that is my problem.  Cylindar
>205 is only about 18Mb into the drive.  There are a total of 754 cylindars
>with 11 heads each on this drive, so I am nowhere near 50Mb when format
>starts having trouble.
>

Don't know if this'll help, but:

I wrote a device driver, from scratch (whew!) to interface a Western Digital
disk controller to which there are attached (1) a Syquest cartridge winchester
and (2) an Atasi 40MB drive.

Now in the Western Digital (WD) controllers, there can be at most 8 heads, but
the cylinder numbers can extend to 2**16 because there are two, 8-bit registers.

In the systems we're discussing, someone could, perhaps, truncate the high 8
bits of the cylinder no. in the driver.

As far as I know, AmigaDOS can support a disk with 2**32 bytes of storage, per
partition. Using MOUNTLIST, you can establish several physical partitions on 
the single physical drive, thus accomodating a drive with more than 2**32 bytes.

				steve childress
				...wlbr!etn-rad!steve   818/706-5247