Conference 7.286::atarist

    When I tried this upgrade I had a problem. GEM/TOS seems happy to
    format the new larger capacity drive, however: MagicSAC/Translator
    refuses to access the additional space. Does anyone have a comment
    or suggestion for me? Thanks!

    Does the MagicSAC/Translator support the Atari double sided drive?
    
    Norbert
    

    Reply to .0,
    
    Are their any written instructions, say with part numbers and
    installation details, around we can get?

    Re: MagicSac + ds drive
    
    Yes. Magic Sac works with double sided drives. But! The Macintosh will
    only deal with ds drives if they use HFS (Hierarchical File System).
    HFS is not in the 64Kb ROMs (MagicSac) but is in the 128Kb ROMs
    (Spectre 128). If you wish to use HFS with the 64Kb ROMs, you must use
    the startup program 'HD20'. Now, I've never been able to make that
    _work_ with the Magic Sac, but Dave Small says it will work...
    				- HBM

    Reply to .4
    
    There were no written instruction for this upgrade.  I did that
    on an experimental basis with the assumption that Atari just
    buys standard drives in the market.  I got ahold of a 720K drive
    for the IBM PC and found that the connectors are the same as the
    one used in the Atari disk case.  So.. I thought I just tried it
    to see what came out of it, worst is smoke? :-)  And.. Bingo! it
    worked.
    
    There really is no specific part number for the drive, there are
    many in the market, TEAC, SONY, FUJI, etc., just get any that is
    advertised to go into IBM PC/XT/AT.  Discard the cable adaptor
    that comes with the drive to go into the IBM power plug and 
    controller cable.
    
    I am wondering whether we can use the 1.44M drive.  I doubt that
    TOS supports 1.44M drives.  Anyone knows?
    
    
    Norbert
    

    Re: .3, .6
    
    My understanding is that the ST would need a new floppy disk controller
    to operate the higher density drives.  Don't waste you money unless
    you are willing to hack the floppy controller on your ST.  I have
    no idea if there are pin compatable Western Digital controllers available.
    
    						-Dave

Well, my Toshiba drive came.  I got it in and working last night.  Read
writes and formats both SS and DS disks so I guess it is working.  I had to
cut a bit of the case too to allow access to the eject button.  Also cut
away about 1/8" from the slot on the ST case so the disk wouldn't get caught
behind the case on eject as this drive sits a little bit lower in the case.

The only potential problems with the toshiba drive (at least the variant
I have) are (1), the connectors were upside down so the ribbon cable needed
to be turned over and it isn't that long so it was dificult to do and
the potential for damage to it (the cable) is there and (2) the ESC on media
change isn't working.  There is a jumper on this drive to select pin 34
from DISK CHANGE to READY and vice versa.  I tried it in both places with no
luck.  Any comments on what I should check here?

Also, the manual that came with it didn't say how to (or where) to terminate
the drive (it suggested leaving A: terminated and using this as B: in the
MS-DOS world).  WHat needs to be done?  It is the only drive in the
system.

So now my $479 520 mono ST is now 1meg RAM (+$100) and DSDD +$85) :-)

Chad

    Attached is a note I grapped off of USENET. I don't know if it will
    help, but it looks like it talks about the same problem you are
    having.

        
        Ray

Subject: Re: Attaching a CHINON drive to the ST
Posted: 10 Feb 89 08:01:46 GMT
Organization: Nixdorf Computer AG, Paderborn, W.-Germany
 
                                            
Now, below there's something concerning the detection of disk changes. I
was wrong in assuming it to be purely a software problem. Actually its both:
listening to 'write protect' and checking serial numbers. That's why
it works worst with write protected disks. A disk change is detected
when you pull out a diskette because the write protect signal becomes
true as soon as the light beam for the write protection is no longer
inhibited by a diskette in the drive. With a write protected disk
it is activated with the diskette in the drive so there is a little
problem in detecting the change of write protected disks. This can be
changed on some drives (see below).
 
Some citations (sorry for badly done interpreting, all books mentioned
are in German):
 
Scheibenkleister, page 297, remarks to media change in connection with
hooking up non-Atari drives to a ST:
 
>...
>Lastly, a few general, well-intended tips and tricks that might help
>you when you want to hook up other drives.
> 
> There are drives that use pin 2 of the Shugart bus (Head Load) to report
> a disk change. The ST detects disk changes in a different manner: it
> regularly checks the state of the write protect pin; to detect disk
> changes properly connect pin 2 of the Shugart bus to pin 28 (Write
> protect) using a diode (for instance a 1N4148). (The diode should permit
> current to pass in the direction of pin 2). This way the disk change 
> signal is modulated onto the write protect signal. This change is 
> for example necessary for the newer TEAC FD35-F drives
> ...
 
Scheibenkleister, page 101, description of diskoriented bios calls:
 
> ...
> Bios call no. 9, called MEDIACH, expects the drive number as input and
> returns the GUESS of the bios, whether the disk in the named drive was
> changed. A return value of 0 means that the BIOS is damned sure the same
> disk is still in the drive; 1 indicates the BIOS is unsure (i.e. with the
> next disk access the serial number in the bootsector will be checked).
> "2" says "You thought I didn't get it but I did: the disk was changed!".
 
Scheibenkleister, page 507, BIOS routines
 
> ...
> In its internal VBL-Floppyroutine (i.e. the routine that is called
> every 50th/60th/70th of a second, depending on your monitor) the TOS
> registers, whether a diskette was changed. The result is kept in an
> internal variable which can be read by MEDIACH. After a write access to
> the boot sector or after formatting TOS always assumes a disk change.
> If the MEDIACH status is 1, TOS will read the boot sector at the next
> disk access to check whether the disk was changed or not (comparison
> of the serial numbers in the boot sector) and, if so, where the data-
> and control sectors are on the new disk. Therfore it is very impor-
> tant to give different serial numbers to all disks.
 
Atari ST Profibuch, page 65, description of the bios function
'Mediach (Bios 9):
 
>...
>Detects disk changes. This works (naturally not at all times) especially
>only when you don't work with write protected disks. In addition, when
>formatting disks you should make sure, that every diskette has a different
>serial number.
>...
> [calls in assembler and C deleted]
>...
>  meret(d0): 0:  disk was certainly not changed
>             1:  maybe the disk was changed <-------------!!!!!
>             2:  disk was certainly changed
>                 (finally three-value-logic!)
>...
>
 
Atari ST Profibuch, page 197, description of system variables
 
>
>...
>  long $00047e    1150     hdv_mediach
>  
>  vector of the routine for detecting the media change status of a logical
>  drive.
>
>...
 
This should answer most questions, if there are still more, feel free to
ask
 
Martin

I assume the 'Shugart bus' talked about is the  connector on back of the
raw drive (34 pin thingy).  Is this so?

CHad

    Yes.
    
    	Ray

Just an interesting note about Write Protect detection.

Everybody seems to assume that a "beam of light" is used for this.  Well, this
is not true in the Chinon drives - I had one drive go bad with the symptoms
of intermittently eported "disk is write protected" when it was not.

The problem?  The little mechanical arm that reaches into the write protect
hole was too short (did I wear it down?) to move the little magnet far
enough away from the reed switch that signals write protection.  I removed
the switch and soldered it in a little further away from the magnet, and it's
fine now.

    There seems to be some confusion based on my reply in .9, I DO NOT
    RECIEVE USENET POSTINGS! If you check the posting date you'll see the
    usenet article was posted on 10-Feb-89, which is before the ROLL::
    subscription service was stopped. I just happened to save some postings
    that I think have usefull reference material, this was one of those. 
    
    	Ray

Well, here is what happened when I looked in to trying various fixes such
as were posted here for the media-change signalling problem.

I found the mentioned diodes at RS -- 10 for .99     With an LN03 copy
of the article I disassmble my ST (not so hard as very few screws are
actually left in it -- usually I just leave everything looking together :-).
I take the drive off, find the correct pins but then I try it one more time
without any changes to show my dad what the problem is and low and behold,
it worked -- the new directory appeared!  I tried it a bunch more times
and it worked.  I guess the connector was just not on it earlier all the way.

Anyway, I had to make no mods to have the corect behavior.  I don't
know what happened except that it definitely beforehand wasn't working and
definitely now is working  with esc.

Happy days!  All is well!

Chad

    I had no problems doing this upgrade using the Radio Shack (TEAC
    inside) dsdd 3.5" drive that was recently on sale.  I appreciate
    this posting, as I was about to hack the cable an attach to the
    
    shack edge connector.  This way it was a breeze.
    dh
    

I ended up having to really solder the diode in.  It works great.  According
to the USENET posting, some drives use pin 2 for disk change.  My drive had
a pin chart and it used pin 2  OR  pin 34, which is jumperable to either
READY or DISK CHANGE signals for XT or AT respectively.  I chose pin 34
jumpered to DC and connected it with pin 28 (write protect detect) with
a 1N1418 diode availble at RS (.99/10).  I soldered it across the bottom
where the edge connector is soldered to the PC board and the pins stick 
through.  It works great now with both write protected disks and non-
write protected disks.  Before, I had been confused and thought it worked
but that was only with write protected disks, which fact I had not noticed
before.  I did seem to have a problem with disk changes signalling write protect
on one format but have been unable to duplicate the problem.

The drive was a 720kb TOSHIBA drive configurable for both XT and AT use.
sub-model FDD4x16 of their normal drive.  Cost $79 plus $6 p/h from TELEMART
in Arizona.  Ad is in BYTE

Chad

Well, the ongoing saga of the toshiba (and from what I here this applies to
quite a few drives out there) dsdd.  I put the diode on as I mentioned earlier.

Everything worked except that sometimes going from a (non?)write protected to
a non-write-protected disk and then trying to write on this non-protected
disk giving problems -- it complains that the disk is write-protected when
it isn't.  According to USENET, this is because the drive doesn't signal
an WP or not when there is no disk in the drive.  Anyway, I hooked up a
$0.40 radio shack mini slider switch to the diode path so that I can break the
diode circuit if I get the write-protect when no write-protect problem.  I
taped the switch to the top of the drive.  The drive sits a bit lower in the
case so it is possible to have the switch in the crack between the top of the
drive and the case -- this also puts a block in so I don't slide disks in
on top of the drive instead of into the drive.

On a related note -- Jameco Electronics in California is selling SONY DSDD
drive mechanisms (without most of the attendant IBM mounting hardware) for
the good price of $69.95 plus about $3 PH UPS ground to Mass.  I ordered on
today for my SF354 to replace that mechanism.  I will report on any problems.

Chad

addendum:  Jameco's number for those interested is

415 -- 592-8097  (that's CA)

That is there 24 hour order line.

Chad

    
    Bizarre problem...installed a brand new Mitsubishi drive in my 1040
    after the old one died and after a bit of futzing (had to mount the
    connector on upside down and change the drive select jumper from 1 to
    0) it read disks fine but won't format or write.  Attempting to write
    to formatted disks blows away some tracks!!
    
    When attempting to write and/or format I hear no head motion.  
    
    ?????
    
    						Brian

    
    
    hi,
    
    Please can I put an appeal for help here under this topic, although
    there may be other places a suitable.
    
    I have an old 520 ST with an external drive. What was supplied was a
    half height Citizon (spell?), which runs off 5V only.
    
    I was at a computer auction the other day, and bought a couple of
    similar Citizon drives for 10 bucks each. They have different part
    numbers, but are 720K douple sided, with the same plugs as my existing
    drive.
    
    I connected both in (one at a time), they Both would not read, but 
    appeared to format and write OK, I can take a Directory of the drive, 
    but if I try to run a program or read from the drive I get a drive not 
    answering alert box. I think that I may be short of a few terminating 
    resistors somewhere, since they so nearly work. Unfortunately due to
    the micro minuture construction of the drives, I cannot see whether my
    old drive is different from the 'new' drives in respect of terminator
    packs. 
    
    Question 1) -   has anyone any reference material with Citizon part
    numbers?
             2) What is the correct termination procedure for the external 
    disk drive ?
    	     3) Anyone had any similar problems, and found a solution?
    
    cheers
    
    Pat.
    
    
    

    Re: .19
    
    Getting more bizarre.
    
    1. Swapped out the SSDD drive in my 520 to the 1040.  Writes/formats
    pefectly. 
    
    2. Tried the Mitsubishi drives in the 520, read is fine, write/format
    still bad.
    
    Is there some sort of jumper on a floppy drive to prevent writing
    (above and beyond the write protect tab sensor)????   
    
    						Brian
    					  Slightly_flipped_out

	This note hasn't had much activity lately, but I'll ask
a question anyway. I must be missing something in the discussion
about replacing a SSDD drive with a generic DSDD. I thought that all
the generic drives had either an edge connector or a dual in-line
pin connector on the back. I opened my external drive case last night,
and found the back of the drive had 2 single in-line pin connectors
on it. One was a 4 pin for power, the other was about 10-20 pins.
Neither was a ribbon cable, but rather, single wires to the connector.
These connectors on the back of the drive don't look generic to me.
What am I missing?

-Andre