timlee@bnrmtv.UUCP (Timothy Lee) (08/01/86)
> An Apple ][ with software disk control will beat a > Radio Shack model II (w/controller) hands down in disk performance. > > * Faster track to track seek time. > * Higher density. > * Fast transfer times. * Much better reliability !!! Early RSTRS80M2 disk drives came up with error nearly 1 out of 8 times with premium disks (with cheapo disks, 1 out of 4). This required the addition of an `external data separator' (whatever). One issue of Byte tells you how to build one, and many issues of Byte had ads trying to sell `external data separators'. > > Also you can operate the disk spinning backward, or lay down spiral sectors. How do you spin the disk backward, other than turning it upside down? Note that turning upside down, while not the best thing for your disks, is possible because the Apple disk drive and software ignore the index hole. Ever notice that when a piece of software has the Apple version on one side of the disk and the other has the TRS80|Atari|Commodore|IBM version, the Apple side is always on the back? That all has to do with index holes.
hsu@eneevax.UUCP (Dave Hsu) (08/03/86)
In article <569@bnrmtv.UUCP> timlee@bnrmtv.UUCP (Timothy Lee) writes: >> An Apple ][ with software disk control will beat a >> Radio Shack model II (w/controller) hands down in disk performance. >> >> * Faster track to track seek time. >> * Higher density. >> * Fast transfer times. > * Much better reliability !!! > Early RSTRS80M2 disk drives came up with error nearly 1 out of 8 > times with premium disks (with cheapo disks, 1 out of 4). This > required the addition of an `external data separator' (whatever). > One issue of Byte tells you how to build one, and many issues of > Byte had ads trying to sell `external data separators'. Two reasons: 1) the old full-height SA350's were, in my book, some of the best drives ever made. Sure, just about everybody else outperformed them in storage, or speed, or something, but when was the last time you had to do a head alignment? The only adjustment that they ever needed was along the lines of calibrating the motor speed. 2) Another testimony to the design of the (bare-bones) 3470 floppy read-write chip. Of course, Western Digital was more concerned with other controller features. >> >> Also you can operate the disk spinning backward, or lay down spiral sectors. > >How do you spin the disk backward, other than turning it upside down? Note Yeah, how DO you spin the disk backwards? I mean, without swapping the polarity of the motor's power connector? -dave -- David Hsu (301) 454-1433 || -8798 || -8715 "I know no-thing!" -eneevax Communications & Signal Processing Laboratory / EE Systems Staff Systems Research Center, Bldg 093 / Engineering Computer Facility The University of Maryland -~- College Park, MD 20742 ARPA: hsu@eneevax.umd.edu UUCP: [seismo,allegra,rlgvax]!umcp-cs!eneevax!hsu "Get back in the cupboard, you pantomimetic regal person..."
langbein@topaz.RUTGERS.EDU (John E. Langbein) (08/07/86)
To Spin a Disk Backwards means you flip the Floppy over to the other side. Apple drives don't use the guide hole. John
greg@utcsri.UUCP (Gregory Smith) (08/21/86)
In article <5517@topaz.RUTGERS.EDU> langbein@topaz.RUTGERS.EDU (John E. Langbein) writes: >To Spin a Disk Backwards means you flip the Floppy over to the other >side. Apple drives don't use the guide hole. > John Yes. Hmm. I know of a couple of problems with this: (1) In normal use, a floppy turns in one direction only, causing any dust in the jacket to get caught in the lining. If you flip the disk, the dust is drawn out again by the opposite rotation. (2) In a real double-sided system, the tracks on one side are offset by half a track from the tracks on the other side, so when a track is written on side A it falls halfway between two tracks on side B. This is done so that the write operation will not weaken the recording on the opposite side. Obviously this does not happen when you flip your disk. This would not be a problem for disks which are rarely (or never) written - e.g. most games. I should add (3) most people do this with SS certified disks, but obviously they deserve their disk errors which are surprisingly rare. Point (1) can be minimized by being very careful about dust, which of course is a good idea anyway. Still, I know several people with large collections of games on 'flipped' disks, many of which 'used to work'. -- "You'll need more than a Tylenol if you don't tell me where my father is!" - The Ice Pirates ---------------------------------------------------------------------- Greg Smith University of Toronto UUCP: ..utzoo!utcsri!greg
ilacqua@bucsb.bu.edu.UUCP (08/26/86)
In article <3277@utcsri.UUCP> greg@utcsri.UUCP (Gregory Smith) writes: >I should add (3) most people do this with SS certified disks, but obviously >they deserve their disk errors which are surprisingly rare. IBM SS drives read and write the top of the disk while apple drives read and write the bottom so, how can there be "SS certified disk?" -- +--------------------------------------------------------------------+ | See these eyes so green? I can stare for a thousand years... | |UUCP: ...!harvard!bu-cs!bucsb!ilacqua | |ARPANET: ilacqua@bucsb.bu.edu | |CSNET: ilacqua%bucsb@bu-cs BITNET: engemnc@bostonu | +--------------------------------------------------------------------+