kriss@AUSTIN.LOCKHEED.COM (R M Kriss) (09/22/90)
Learn something new about Macs everyday. A friend mailed me a disk formatted
for 1.4M. My Mac Plus could not read the disk, so I reformatted it to 800K and
sent it back to him. His Mac with the HD drive could not read the disk. He
sent it back to me and it worked great.
I think the problem is with the HD drive. They can read 400k or 800K disks
formatted on a nonHD drive but cannot read a HD disk reformatted on a nonHD
drive. Heads-up reformatting HD disks.
I am planning to buy an SE/30 soon. Maybe I can get around the reformatting
problem by using my old 800K Apple external drive. Can a SE/30 read a 800K
reformatted HD disk on the external drive? Will the old external drive even
work on an SE/30?
Dick
=====================================================================
Richard (Dick) Kriss E-Mail: kriss@austin.lockheed.com
904 Dartmoor Cove Packet Radio: SP KD5VU @ KB5PM.#AUS.TX.USA.NA
Austin, Texas 78746 Phone: 512-448-5153 (day) or 327-9566 (evenings)
My employer has nothing to do with this message! ... _._
===================================================================== dyer@spdcc.COM (Steve Dyer) (09/22/90)
In article <369@shrike.AUSTIN.LOCKHEED.COM> kriss@AUSTIN.LOCKHEED.COM (R M Kriss) writes: >I think the problem is with the HD drive. They can read 400k or 800K disks >formatted on a nonHD drive but cannot read a HD disk reformatted on a nonHD >drive. Heads-up reformatting HD disks. The solution is simple--place a piece of tape over the HD indicator hole on the HD floppy which was formatted to 800K when inserting it in the SuperDrive. -- Steve Dyer dyer@ursa-major.spdcc.com aka {ima,harvard,rayssd,linus,m2c}!spdcc!dyer dyer@arktouros.mit.edu, dyer@hstbme.mit.edu
c60b-4ah@e260-2b.berkeley.edu (Phantom) (09/24/90)
If you stick a opaque tape on you High Density disk so that the hole that distinguishes it form a 800k disk is covered, it will probably work on a FDHD (for a short while). That hole is used by FDHD to identify the density the disk in it. It is a useful feature not only because it enables you to format a disk without having to tell the computer the density of the disk every time, which is something you have to do on a PS/2, but also because it prevents people from accidentaly format a DD disk in HD format or the other way around. Because the surface coating of HD and DD disks have quite different physical properties, one should refrain from cross-formating them. Time and chance are all it takes your data to vanish if you insist on doing so.
Garance_Drosehn@mts.rpi.edu (Garance Drosehn) (09/25/90)
In article <369@shrike.AUSTIN.LOCKHEED.COM> kriss@AUSTIN.LOCKHEED.COM (R M Kriss) writes: ...some stuff deleted... > I am planning to buy an SE/30 soon. Maybe I can get around the > reformatting problem by using my > old 800K Apple external drive. Can a SE/30 read a 800K reformatted > HD disk on the external drive? Will the old external drive even > work on an SE/30? Your old 800K external drive will work on the SE/30. On the other hand, I'm about to get rid of the 800K drive on my SE, because disks can get screwed up if you put an HD disk (formatted as an HD disk) into that 800K drive. The 800K drive has no idea about HD disks, so it thinks the disk is not initialized. If your software auto-formats uninitialized disks (as I have DiskFit setup to do), the disk is zapped before you know it. In my opinion, the moral of the story is to use 800K disks for 800K formats, and HD disks in HD formats. If you have an SE/30, there's no good reason to format HD disks as 800K disks. Garance_Drosehn@mts.rpi.edu ITS Systems Programmer Rensselaer Polytechnic Institute; Troy, NY. USA