shatara@memit.enet.dec.com (Chris Shatara) (03/13/90)
I pulled down a DOS 3.3 application from AmericaOnline last night and unpacked it to a DOS 3.3 formatted disk with shrinkit and all went fine. The program is not self starting. The disk will boot and then give a mesasge file not found. There's a "HELLO" file on the disk and loading it and running it causes the application to run fine. Question how do I specify that I want the "HELLO" program to be executed at startup. If you couldn't guess, I hardly ever use DOS 3.3 so I have ZERO documentation on it. Thanks...Chris ============================================================================= | Chris Shatara | Internet: shatara@memit.enet.dec.com | | Opinions expressed are | DEC Easynet: memit::shatara | | mine and mine only! | UUCP: ...!decwrl!memit!shatara | =============================================================================
taxman@drycas.club.cc.cmu.edu (Mike Wommack) (03/14/90)
> Question how do I specify that I want the "HELLO" program to be executed > at startup. If you couldn't guess, I hardly ever use DOS 3.3 so I have > ZERO documentation on it. > Copy 2 plus has an option to change the boot file within the DOS image. Also, if you have a DOS 3.3 system disk handy, there is a file on there .I cant remember the name of it, I think it's MUFFIN that will also change the name of the boot file within the DOS image. Mike...Ya know it! Taxman@Drycas Taxman@Drycas.Club.Cc.Cmu.Edu Drycas::Taxman !Uunet!Drycas.Club.Cc.Cmu.Edu!Taxman How can ya dis me when ya don't even know me?
cs122aw@ux1.cso.uiuc.edu (Scott Alfter) (03/14/90)
In article <1441@mountn.dec.com> shatara@memit.enet.dec.com (Chris Shatara) writes: >Question how do I specify that I want the "HELLO" program to be executed >at startup. If you couldn't guess, I hardly ever use DOS 3.3 so I have >ZERO documentation on it. Sounds to me like they didn't supply an unaltered copy of DOS 3.3. If you have a sector editor (Copy II Plus has one), you should find the name of the startup program in track 1, sector 9. This is an ordinary string with the high bits set and no length byte, unlike ProDOS. Change the string to "HELLO" followed by as many spaces are needed to erase the old name. Write the sector back to disk and reboot. All should work with no problem. (This, of course, assumes that you have DOS 3.3. If you have Pronto-DOS or Diversi-DOS, the location of the filename may be different. Get back with me and let me know if it worked. If not, I'll take a look at Pronto-DOS and Diversi-DOS and find the addresses of the startup filenames for them.) Scott Alfter------------------------------------------------------------------- Internet: cs122aw@ux1.cso.uiuc.edu _/_ Apple II: the power to be your best! alfter@mrcnext.cso.uiuc.edu/ v \ saa33413@uxa.cso.uiuc.edu ( ( A keyboard--how quaint! Bitnet: free0066@uiucvmd.bitnet \_^_/ --M. Scott, STIV
cs122aw@ux1.cso.uiuc.edu (Scott Alfter) (03/14/90)
In article <227.25fd7eb3@drycas.club.cc.cmu.edu> taxman@drycas.club.cc.cmu.edu (Mike Wommack) writes: >Copy 2 plus has an option to change the boot file within the DOS image. >Also, if you have a DOS 3.3 system disk handy, there is a file on there >.I cant remember the name of it, I think it's MUFFIN that will also >change the name of the boot file within the DOS image. And I told him to use the sector editor in Copy II Plus to fix the startup program! C'est la vie... As for the DOS 3.3 System Master, MUFFIN is the program that converts files from the 13-sector format used by DOS 3.2 (and earlier versions of Apple DOS) to the 16-sector format used by DOS 3.3. Earlier versions of Copy II Plus (I think before 6.0) would also do this conversion, as well as make 13-sector 5.25" disks. I did this once or twice just to play around, but it was never usable because I didn't have DOS 3.2 to boot into. It would also have been impractical because I would have had to boot DOS 3.3 and run START13 to boot a DOS 3.2 disk. (The disk controller in 99% of Apple 5.25" drives in existence is a 16-sector controller, though I did see a 13-sector controller (C) 1978 in a used-computer-parts store a few weeks ago.) Finally, there's the simple matter that you lose about 19% of your disk capacity. DOS 3.3 was a significant advance in Apple DOS; ProDOS, of course, uses 16-sector disks because most drive systems out in 1983 were, of course, 16-sector drives. That's your history lesson for today. Class is dismissed. :-) Scott Alfter------------------------------------------------------------------- Internet: cs122aw@ux1.cso.uiuc.edu _/_ Apple II: the power to be your best! alfter@mrcnext.cso.uiuc.edu/ v \ saa33413@uxa.cso.uiuc.edu ( ( A keyboard--how quaint! Bitnet: free0066@uiucvmd.bitnet \_^_/ --M. Scott, STIV
jacques@enovax.dec.com (Norman Jacques) (03/14/90)
>Question how do I specify that I want the "HELLO" program to be executed >at startup. If you couldn't guess, I hardly ever use DOS 3.3 so I have >ZERO documentation on it. Load the file into the system as if you were going to run it. Then get a new disk, place into the disk drive and type INIT hello. This will format the disk and place a copy of whatever in memory as the hellp program. ******************************************************************************** * * * Norman Jacques DEC EASYNET. ENOVAX::JACQUES * * DIGITAL EQUIPMENT CORP. INTERNET. DECWRL::"JACQUES@ENOVAX.ENET.DEC.COM" * * ENFIELD, CT. 06082 * * * ********************************************************************************
cnhst@unix.cis.pitt.edu (Christine N. Helferty) (03/15/90)
> Question how do I specify that I want the "HELLO" program to be executed > at startup. If you couldn't guess, I hardly ever use DOS 3.3 so I have > ZERO documentation on it. If you have COPY II+, I think it has an option to change the boot program for the disk. Otherwise, the easiest way to do it (i.e. without sector editing) would be to load the HELLO program into memory (LOAD it, but don't RUN it), and then place a blank disk in the drive and say "INIT HELLO". This formats the new disk and places the Hello program on it as the Boot program. You would then have to use some copy utility (try FID from the DOS 3.3 master disk) to copy the rest of the files from the original disk.
muller@Alliant.COM (Jim Muller) (03/15/90)
It has been a while since I did much 3.3 stuff, but if I remember right...
DOS3.3 does not run HELLO per se as the startup program. If you
initilize (format) the disk by giving it some other name (you do that
with INIT <filename> don't you?) it looks for whatever filename was used.
At some later time, you can modify the HELLO program, but I don't know
what happens if you just rename HELLO. If you create a file named HELLO
on a disk that was initilized with another name, HELLO will not be the
startup program. HELLO is not a required startup name, but is only
recommended (or was, anyway) by Apple so as to provide some standard.
--
- Jim Mullerjefft@gnh-applesauce.cts.com (Jeff Tarr Jr.) (04/09/90)
Okay, I was dissassembling the SEEKABS routine in the DOS 3.3 code that seeks
the read/write head and it appears that DOS 3.3 has the capability of seeking
and writing to half tracks as well as full tracks. I was wondering what the
reason for this was, and does this fact slow down disk access? To read a full
track, SEEKABS must be called in a loop twice, essentially seeking a double
half track to yield a full track, which seems to be wasteful, unless The Woz
originally had plans of formatting or using half tracks and then abandoned it.
I wanted to know if anyone knew why this was done in this way.
Jeff Tarr Jr.. Sysop of the AppleSauce BBS [212] 721-4122...
America Online: Klorn UUCP: jefft@gnh-applesauce.cts.com
* Sent by AppleSauce at Sun, 8 Apr 90 11:32:24stephens@latcs1.oz.au (Philip J Stephens) (04/09/90)
In article <9004082354.AA20755@apple.com>, Jeff Tarr Jr. writes: > > Okay, I was dissassembling the SEEKABS routine in the DOS 3.3 code that seeks > the read/write head and it appears that DOS 3.3 has the capability of seeking > and writing to half tracks as well as full tracks. I was wondering what the > reason for this was, and does this fact slow down disk access? The disk drive has 80 tracks (which you've called "half tracks"), devided into groups of 4. A four-phase stepper motor moves the arm from track to track in either direction. Since the read/write head is too big, you can only use every second arm position as a track. However, you can't just skip over every second track position because of the way the stepper motor works, which is why the routine is called twice. Basically, to move the arm from one position to the next, you must turn on the destination phase, delay for a while until the motor gains enough speed (or something to that effect), and then turn off the source phase. I'm pretty sure you are not allowed to skip over a phase - or at least, the head doesn't move properly if you try it. (I may be wrong, of course.) Thus, I don't think there is a faster way of moving the head, except for playing around with the current phase delays (which are probably optimal already). [Just as an aside, the image of a track tends to "leak" over onto the half- track positions, which is taken advantage of by Locksmith's disk recover function in order to restore trashed disks.] </\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\></\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\> < Philip J. Stephens >< "Many views yield the truth." > < Hons. student, Computer Science >< "Therefore, be not alone." > < La Trobe University, Melbourne >< - Prime Song of the viggies > <\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/><\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/>
dseah@wpi.wpi.edu (David I Seah) (04/09/90)
In article <9004082354.AA20755@apple.com> jefft@gnh-applesauce.cts.com (Jeff Tarr Jr.) writes: >Okay, I was dissassembling the SEEKABS routine in the DOS 3.3 code that seeks >the read/write head and it appears that DOS 3.3 has the capability of seeking >and writing to half tracks as well as full tracks. I was wondering what the >reason for this was, and does this fact slow down disk access? To read a full >track, SEEKABS must be called in a loop twice, essentially seeking a double >half track to yield a full track, which seems to be wasteful, unless The Woz >originally had plans of formatting or using half tracks and then abandoned it. >I wanted to know if anyone knew why this was done in this way. Yep! SEEKABS is called twice to step for "half tracks". The reason why DOS 3.3 doesn't use half tracks is because the read/write head is too wide...attempt to write on an adjacent half track will destroy the original track. I'm not sure if its possible to actually step two half tracks in one go...my understanding was that the stepper motor was such that you couldn't do anything else. But then again, there were quarter-track protections...coupled with other relatively simple synchronized and spiral-tracking routines would break just about any automated bit copier, hehehe. -- Dave Seah | O M N I D Y N E S Y S T E M S - M | "I sacrifice this cat to | User Friendly Killing Machines | Cognitive Science!" - MEK .............................................................................. I-net: dseah@wpi.wpi.edu - America Online: AFC DaveS (Apple II Art & Graphics)
toddpw@tybalt.caltech.edu (Todd P. Whitesel) (04/09/90)
jefft@gnh-applesauce.cts.com (Jeff Tarr Jr.) writes: >Okay, I was dissassembling the SEEKABS routine in the DOS 3.3 code that seeks >the read/write head and it appears that DOS 3.3 has the capability of seeking >and writing to half tracks as well as full tracks. I was wondering what the >reason for this was, and does this fact slow down disk access? To read a full >track, SEEKABS must be called in a loop twice, essentially seeking a double >half track to yield a full track, which seems to be wasteful, unless The Woz >originally had plans of formatting or using half tracks and then abandoned it. >I wanted to know if anyone knew why this was done in this way. If you write a track on the disk, the magnetic field isn't razor thin. It's wide enough to effectively write on the adjacent quarter tracks, and partially (i.e. gobs of unpredictable errors) on the adjacent half tracks as well. It might slow things down if a single routine can optimize the stepping time for long seeks... I think the settling time and track read time are far more significant, so the speed impact of rewriting SEEKABS would be minimal. (I could be wrong.) But it is for that reason that data is never stored closer than 3/4 of a track apart, and since 1/4 tracks are a pain to work with (you have to do gross things with the stepper magnets) DOS only uses full tracks to store data. Spiral tracking copy protection schemes use quarter tracks but spiral it such that data is never closer than 3/4 track at any point on the disk (assuming they are reading real data and not checking for the presence of intentional errors). I suspect that Woz wrote it this way to keep the code simpler or (more likely) smaller. 13 sector DOS didn't have as many unused spots as 16 sector DOS does. Todd Whitesel toddpw @ tybalt.caltech.edu
cyliao@eng.umd.edu (Chun-Yao Liao) (04/09/90)
In article <9004082354.AA20755@apple.com> jefft@gnh-applesauce.cts.com (Jeff Tarr Jr.) writes: >Okay, I was dissassembling the SEEKABS routine in the DOS 3.3 code that seeks >the read/write head and it appears that DOS 3.3 has the capability of seeking >and writing to half tracks as well as full tracks. I was wondering what the >reason for this was, and does this fact slow down disk access? To read a full >track, SEEKABS must be called in a loop twice, essentially seeking a double >half track to yield a full track, which seems to be wasteful, unless The Woz >originally had plans of formatting or using half tracks and then abandoned it. >I wanted to know if anyone knew why this was done in this way. > >America Online: Klorn UUCP: jefft@gnh-applesauce.cts.com The Apple's 5.25 driver has to move the head two tracks to make one track of data on the disk. The reason was that the head was too wide to fit in every track without interfere the adyacent tracks. Therefore, Woz designed the DOS to move twice the step motor to get one usable track. If the head was small enough, we can actually get 4 times of memory for each side. Most of today's driver can handle 1/4 track (or actually 1/2 hardware track) by the way. AFter all, remember that the 5.25 driver's technology is about 10 years old, and havent changed for the compatibility. -- cyliao@wam.umd.edu o NeXT : I put main frame power on two chips. @epsl.umd.edu o people: We put main flame power on two guys. @bagend.eng.umd.edu o :::::::::::::::::::::::::::::::::::::::::::: xxxxx@xxxxx.xxx.xxx (reserved) o RC + Apple // + Classic Music + NeXT = cyliao
alfter@MRCNEXT.CSO.UIUC.EDU (Scott Alfter) (04/10/90)
toddpw@tybalt.caltech.edu (Todd P. Whitesel) writes:
------------------------------------start------------------------------------
But it is for that reason that data is never stored closer than 3/4 of a track
apart, and since 1/4 tracks are a pain to work with (you have to do gross
things with the stepper magnets) DOS only uses full tracks to store data.
Spiral tracking copy protection schemes use quarter tracks but spiral it
such that data is never closer than 3/4 track at any point on the disk
(assuming they are reading real data and not checking for the presence of
intentional errors).
------------------------------------end-------------------------------------
So what you're saying is that disk space isn't currently being as efficiently
used as it could? I'm forever seeking ways to jam more than 140K on a disk.
Apple's newer drives (DuoDisk, Apple 5.25, IIc internal) are supposed to handle
38 tracks with no problem (I have a DuoDisk), and the Disk II (and most of the
drives modeled after it) are supposed to take a full 40 tracks. Why settle on
a piddly 140K when you can get 152K? Your comment raises another possibility,
though. If three-fourths of a track is a safe spacing, then even on the newer
drives it should be possible to get 50 of the 3/4-tracks, for 200K on a side!
Biggest problem here is that while you only have to poke one byte and fix the
volume bitmap to get ProDOS to accept more than 35 tracks, it would take a
major MLI hack to deliver 200K--not to mention that it would probably end up
breaking the current format unless there's room for almost a whole new driver
in ProDOS 8, and a way to distinguish between the "extended" disks and normal
disks. (Anyone at Apple care to comment on this?) Besides, I can't figure out
how to get anything less than half-tracks; you say quarter-tracks are a mess
to get from the drive. Just what is involved in quarter-tracking? I have
some material on how 5.25" drives work (including Beneath Apple ProDOS), but
their documentation would have you believe that only half-tracks are normally
possible. (I have seen quarter-tracks in copy programs, though.)
Scott Alfter-------------------------------------------------------------------
Internet: alfter@mrcnext.cso.uiuc.edu _/_ Apple II: the power to be your best!
cs122aw@ux1.cso.uiuc.edu / v \
saa33413@uxa.cso.uiuc.edu ( ( A keyboard--how quaint!
Bitnet: free0066@uiucvmd.bitnet \_^_/ --M. Scott, STIVtoddpw@tybalt.caltech.edu (Todd P. Whitesel) (04/10/90)
alfter@MRCNEXT.CSO.UIUC.EDU (Scott Alfter) writes: [ in response to my comment that it is safe to write data 3/4 of a track apart even though it is a royal pain ] >So what you're saying is that disk space isn't currently being as efficiently >used as it could? I'm forever seeking ways to jam more than 140K on a disk. No! No! Don't even think about it! Quarter tracks are only used by copy protection schemes and by nibble copiers. You do NOT want to use them for everyday data storage. 1. Accessing quarter tracks requires that you hold the drive head between two half tracks. This requires you to hold two adjacent stepper magnets on _while_ reading and writing the actual data. I don't think this is a reliable way to store data -- somebody who knows more than I do can explain why it is not a good operating position for the drive. 2. Modifiying the O/S would be an unholy bitch. I suggest you stick to 40 tracks -- or invest in a universal drive controller and a 3.5 drive. It may be throwing money at the problem but you avoid a LOT of headaches. Todd Whitesel toddpw @ tybalt.caltech.edu
kadickey@phoenix.Princeton.EDU (Kent Andrew Dickey) (04/10/90)
[ Lots of stuff from lots of people deleted.... ] Ah...the intricacies of Apple // disk software. A quick introduction to disk arm moving: Moving the Disk II drive arm requires turning on stepper magnets in a specified order, with specified delays. Imagine it as pulling the drive arm around using a magnet which you keep moving in front of it. These magnets can take one of four different phases--and once you've stepped through each phase once, you start over with the first one again. "Stepping" consists of turning these magnets on and off at specified minimum times (After you turn the magnet on, you have to make sure the drive arm GETS there before you go to the next phase!). Each cycle through these 4 phases is generally referred to as "one phase" or "one half track." Yeah, computer terminology is meant to be confusing. :-) Why is it only a half-track? As others have pointed out, the drive read/write head is quite large physically--large enough to cause its magnetic field to scramble stuff a phase away. Therefore, writing on every phase is impossible. So, Woz decided to just make every OTHER phase a TRACK, and so we get 35 tracks on our 70 phase drive mechanisms. So, half-tracks are very easy to seek to and copy-protection writers soon started using them to store valid data (using the data layout of: Tracks 0, 1.5, 2.5, 3.5, etc...So all the data was AT LEAST 2 phases apart). These protections are easily defeated by merely copying the proper tracks. Little known fact: some old protected software had its data written using a higher density disk mechanism, i.e., one that COULD write to consecutive phases on the disk (half-tracks). The Disk II drive head could READ this data, but never reproduce it--leading to the first un-bit-copyable software (unless you bought the same type of disk drive). I believe mostly this consisted of using tracks 4, 4.5, and 5, and the copy protection software just checked for certain valid data on all three of those. I would assume that the data would be slightly flaky (since the drive couldn't WRITE it at that density, READing might be a little iffy on some drives), so I wouldn't want a full disk of 80 tracks of important information stored on the disk.... OK, so what about half tracks? Conceptually, it's pretty simple. Remember how we're leading the drive arm around the disk by pulling it ahead by turning on magnets in a specified sequence? Well, how about after engaging, say, the third phase of the 4-cycle phase transition, we turn on phase two SIMULTANEOUSLY? Ah...now, the drive arm centers itself nicely BETWEEN the two positions!! Let it settle there a short while, and shut both magnets off simultaneously, and we've just seeked to a 1/4-track. Clearly, this is not the most accurate of positionings (if the magnets do not put out exactly the same amount of power, then the head will be pulled more to one side then the other...), so you probably wouldn't want to trust various disk drives to seek properly to this position. However, since writing doesn't seem to affect data 3/4 of a track away, it's conceptually possible to format a disk using 3/4 track spacing (giving 140/3 = 46 tracks == 44K extra). No one that I know of has ever tried doing this...mostly, I assume, because the 1/4 track position is not all that accurate... So, why have we all heard of 1/4 tracks then? Well, Broderbund pioneered a real nasty protection scheme (I believe first used on Choplifter) called track spiralling. The idea is to write, say, 3 sectors on track 1, in the middle of the track seek to the next higher 1/4 track (1.25), write another 3 sectors, seek to track 1.5, write another 3 sectors, etc. The reason for only 3 sectors per quarter-track is that the data CANNOT overlap closer than 3/4 of a track away, and due to a certain amount of time required to move the drive arm, this space was lost. However, if space was not a premium, this is a difficult protection scheme to copy....(Note, it's called track spiralling since the data looks like it spirals outward from the center). Other neat Disk II facts: The SEEKABS routine already optimizes the timing delays to move the drive arm as fast as possible. That is, it's smart enough to know that once the drive arm has picked up momentum, it needn't wait as long to move it forward yet another track! Similarly, it does the reverse to slow it down when it approaches the destination track. Thus, seeking from track 35 to track 0 is quite quick, much faster than calling SEEKABS to step from 35 to 34, and then to 33, and then, etc....It's impressive that it can achieve this result using so little code. (Well, alright, it's not 'optimal', but it has to operate within the tolerance of the drive mechanism...as in, on your drive, you might be able to get by with lower delays, while my 10 year old drive might need every last microsecond of delay in order to work properly). For any more Disk II trivia/information, feel free to send me e-mail. (I haven't even covered DATA FORMATS on the disk itself, just how to move the arm around....it's pretty easy to get 18 sectors per track, and there is a VERY complicated way to get nearly 20 sectors!) So, 20 sectors/track * ( 40 * 4/3) = 1060 sectors = 265K, on one side of the disk! Therefore, the Disk II can store 530K on the two sides of a SINGLE density disk, whereas IBM's double density disk can only hold 360K on two sides! Oh, and this is all done in software... Kent Dickey kadickey@phoenix.Princeton.EDU
skann@gnh-applesauce.cts.com (Steve Kann) (04/10/90)
Well, I never knew EXACTLY why this was done, But I remember (back in
the old days..) when the copy programs (like nibbles away, or copy II plus 5.0)
would have those features, and I also remember a few times when they used them
(Although I never understood why?)..
Proline:skann@gnh-applesauce <--- Preferred
America online: NYSteve
CI$:70265,1141
************************
UUCP: !crash!pnet01!gnh-applesauce!skann This is just my opinion!
INET: skann@gnh-applesauce.cts.com ************************
ARPA: crash!pnet01!gnh-applesauce!skann@nosc.mil "Don't blame me!"
* Sent by AppleSauce at Mon, 9 Apr 90 14:29:27cyliao@eng.umd.edu (Chun-Yao Liao) (04/12/90)
In article <9004091826.AA14659@mrcnext.cso.uiuc.edu> alfter@MRCNEXT.CSO.UIUC.EDU (Scott Alfter) writes: >So what you're saying is that disk space isn't currently being as efficiently >used as it could? I'm forever seeking ways to jam more than 140K on a disk. >Apple's newer drives (DuoDisk, Apple 5.25, IIc internal) are supposed to handle Nope, I believe that's the only way to assure your data not to be disturbed by writing next to the data track. Remember, the Apple 5.25 driver's head is just TOOOOOO wide that actually covers entire 1/4 track and usually spread to 1/2 track.Therefore, you need at least 1 full track of distance between each data track. (remember, writting to the track 5 will intefere data on track 5.5 and 4.5, writting on track 6 will interfere data on 5.5 and 6.5, so if you try to write the data of track 6 to 5 3/4 track, then it will intefere track 5.25 which is right under the head if reading track 5. See, you MUST leave 1 full track of distance between each data track.) >38 tracks with no problem (I have a DuoDisk), and the Disk II (and most of the >drives modeled after it) are supposed to take a full 40 tracks. Why settle on >a piddly 140K when you can get 152K? Your comment raises another possibility, >though. If three-fourths of a track is a safe spacing, then even on the newer >drives it should be possible to get 50 of the 3/4-tracks, for 200K on a side! >Biggest problem here is that while you only have to poke one byte and fix the >volume bitmap to get ProDOS to accept more than 35 tracks, it would take a >major MLI hack to deliver 200K--not to mention that it would probably end up >breaking the current format unless there's room for almost a whole new driver >in ProDOS 8, and a way to distinguish between the "extended" disks and normal >disks. (Anyone at Apple care to comment on this?) Besides, I can't figure out sure, you can easily modify the dos to use extra tracks (just few bytes, or one byte? I don't remember) but again, you can't use 3/4 track. >how to get anything less than half-tracks; you say quarter-tracks are a mess >to get from the drive. Just what is involved in quarter-tracking? I have >some material on how 5.25" drives work (including Beneath Apple ProDOS), but >their documentation would have you believe that only half-tracks are normally >possible. (I have seen quarter-tracks in copy programs, though.) yes, but newer half-high drivers can handle 1/4 track without problem. It involves the control of step motor. You make step motor's magnet to move the head by 1 hard track (1/2 data track) , but activate the magnet to move it back at same time. In this case, the head receive the force of magnet at same time so it stay at somewhere half way to each hardware track, that's 1/4 data track and the socalled quatertrack. You can use your manual to figure out how to control step motor. -- cyliao@wam.umd.edu o NeXT : I put main frame power on two chips. @epsl.umd.edu o people: We put main flame power on two guys. @bagend.eng.umd.edu o :::::::::::::::::::::::::::::::::::::::::::: xxxxx@xxxxx.xxx.xxx (reserved) o RC + Apple // + Classic Music + NeXT = cyliao
rhood@pro-gsplus.cts.com (Robert Hood) (04/12/90)
In-Reply-To: message from kadickey@phoenix.Princeton.EDU Re: 530K per disk on a Disk II Is there any way to alter the ProDOS Disk II driver to do this? Also, how would one modify such a driver for drives that are 40 (not 35) track capable? Robert Hood - programmer ProLine address: pro-gsplus!rhood InterNet address: rhood@pro-gsplus.cts.com
nagendra@bucsf.bu.edu (nagendra mishr) (04/13/90)
I would be interested to know more about these schemes. What do the IBM drives do, the 1.2 meg floppy's. Do you know anything about the 2 inch drives Apple was thinking about? and A little while ago, in incider, they mentioned something about a 3.5" hard drive on a card from some international company. thanks nagendra