ir320@sdcc6.UUCP (ir320) (10/05/85)
Hello netlanders,
I am getting a new computer and need to decide whether to get 96 tpi drives
or 48 tpi drives. I know I get double the storage with 96 tpi, but I also
give up disk compatability with them don't I? Is there a way I could
read/write a 48 tpi disks on a 96 tpi machine. (The system is question
is the new SB180 system described in Byte.) Can other systems write disks
for these drives?
John Antypas
UC San Diego
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STANLEY@USC-ECLB.ARPA (10/10/85)
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Date: 5 Oct 85 16:37:40 GMT
From: ir320 <ir320%sdcc6.uucp@BRL.ARPA>
To: info-cpm@AMSAA.ARPA
Subject: A way to read 48 tpi disks on 96 tpi drives?
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Message-ID: <2229@sdcc6.UUCP>
Newsgroups: net.micro.cpm
Hello netlanders,
I am getting a new computer and need to decide whether to get 96 tpi drives
or 48 tpi drives. I know I get double the storage with 96 tpi, but I also
give up disk compatability with them don't I? Is there a way I could
read/write a 48 tpi disks on a 96 tpi machine. (The system is question
is the new SB180 system described in Byte.) Can other systems write disks
for these drives?
John Antypas
UC San Diego
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--------------------
John,
You can read 48 tpi disks on 96 tpi drives by double-stepping the
head for each track; Heath H89's have been doing this for a long
time. Writing in 48 tpi from a 96 tpi drive is another thing.
I've been told it can be done, and have seen it happen
occasionally on an IBM PC/AT, but my experience tells me it is a
very dicey business. Reading can be done dependably, but not
writing.
...Dick StanleyKushall.henr@XEROX.ARPA (10/10/85)
I have a DEC Rainbow that uses DEC RX50 single sidded 96 tpi drives, under MS-DOS I can read IBM PC single sidded 48 tpi disks. There is also a program called Media Master that allows reading(and writing) of many popular 96 & 48 tpi disks. MM even allows the 96 tpi drive to format a disk to the popular 48 tpi formats, Kaypro, IBM PC, Osborne. One problem that can occur in writing is that the 96 tpi head width is narrower than with a 48tpi drive (At least DEC claims it is) and a 48 tpi drive might have trouble reading a 48 tpi disk written with a 96 tpi drive. I have had very good results with this, but always use a 'new' disk to avoid data residue that could be left from a 48 tpi write that may not erase completly with a 96 tpi head. To make a long story short, with the right software you can read the 48 tpi disks on the 96 tpi drives! ED KUSHALL
bobh@pedsgd.UUCP (Bob Halloran) (10/11/85)
Organization : Perkin-Elmer DSG, Tinton Falls NJ In article <2229@sdcc6.UUCP> ir320@sdcc6.UUCP (ir320) writes: >I am getting a new computer and need to decide whether to get 96 tpi drives >or 48 tpi drives. I know I get double the storage with 96 tpi, but I also >give up disk compatability with them don't I? Is there a way I could >read/write a 48 tpi disks on a 96 tpi machine. (The system is question >is the new SB180 system described in Byte.) Can other systems write disks >for these drives? A 96tpi drive CAN read disks written on a 48tpi drive; the second part of the construction article for that same SB180 implies as much. The BIOS needs some extra code to realize it must double-step for these disk formats. The major problem as I understand it is that in writing, the 96tpi drive lays down a narrower 'track' than the 48tpi drive (makes sense), which may either get lost against a previously written 'wide' track if the disk has been used before in a 48tpi drive, or simply be too narrow for the 48tpi drive's head to get a useful signal from. Hope this helps. Bob Halloran Sr MTS, Perkin-Elmer DSG ============================================================================= UUCP: {decvax, ucbvax, most Action Central}!vax135\ {topaz, pesnta, princeton}!petsd!pedsgd!bobh ARPA: petsd!pedsgd!bobh@topaz USPS: 106 Apple St M/S 305, Tinton Falls NJ 07724 DDD: (201) 758-7000 Disclaimer: My opinions are my own. Quote: "It's Reagan's fault. Everything's Reagan's fault. Floods... volcanoes... herpes... Reagan's fault." -- Editor Overbeek, Bloom Beacon
cem@intelca.UUCP (Chuck McManis) (10/11/85)
> I am getting a new computer and need to decide whether to get 96 tpi drives > or 48 tpi drives. I know I get double the storage with 96 tpi, but I also > give up disk compatability with them don't I? Is there a way I could > read/write a 48 tpi disks on a 96 tpi machine. (The system is question > is the new SB180 system described in Byte.) Can other systems write disks > for these drives? The Ampro can read 48TPI disks on 96TPI drives, and since Joe Wright wrote the BIOS for the SB180 and is/was heavily involved in the Ampro software I suspect the SB180 will also support this capability. Another solution is to spend the $20 for a single sided 48TPI drive and use it as a spare for compatibility purposes. --Chuck -- - - - D I S C L A I M E R - - - {ihnp4,fortune}!dual\ All opinions expressed herein are my {qantel,idi}-> !intelca!cem own and not those of my employer, my {ucbvax,hao}!hplabs/ friends, or my avocado plant. :-}
VOORHEIS.ES@XEROX.ARPA (10/15/85)
We recently purchased a Compaq AT compatable and were having trouble formating diskettes. The unit has one 96tpi and one 48tpi drives. After talking with the service people at the store, here is the summary: -a 96 tpi drive can read and write* 48 tpi format. -a 48 tpi drive can read diskettes formated to 48 tpi by a 96 tpi drive. -use High Density media when writing with 96 tpi drives. -use double density media when writing with 48 tpi drives. *We were told that 96 tpi drives heads are narrower and that the write current is different than 48 tpi drives. Therefore, 48 tpi drives cannot write on HD media and 96 tpi drive cannot write on 2D (double density media).