64K ROMs and 800K floppy

[Mac128]

Yes, that is true for the internal drive if you are trying to use the MFD-51W-03 with the red cable, however, he is talking about an external drive. All external drives are properly configured to avoid this problem. There is no need to cut anything inside an external drive unless you are using it on a computer not compatible with it ... and the 512K is listed as compatible: http://docs.info.apple.com/article.html?artnum=10268

Pina's instructions to cut the ribbon cable (which as far as I know only appears in the Dead Mac Scrolls, page 249) refer specifically to the internal drives ONLY. The problem he's having with the external drive I suspect is ROM related and cannot be changed without altering the circuit board on the drive or re-writing the 64K ROM since this is a pre-system hardware issue that goes away when you load a system disk. Also, the red cable is designed for use with 400K drives or 800K drives that have the socket header disconnected, so all wires are connected. The original 800K drives disabled the speed control pin at the header since it was unnecessary for the them, so it doesn't matter which cable is used. The newer 800K drives did not, probably so that pin could be used for other purposes as you suggest (eg the IIGS). Whatever the reason, the yellow cable was required which disabled the those pins inside the Macintosh. If you used a red cable with the newer drives, the speed control signal is passed through and the drive goes into an endless spinning & eject cycle. Pina's instructions in Dead Mac Scrolls are greatly simplified and designed to solve your problem without explaining it, necessarily. So clipping the red cable wires with the newer drives would solve the problem, particularly since there are some newer drives with the same part number as the old (confusing indeed). But again, totally unnecessary on the external drive. Cutting those wires on the A9M0106 probably will cause it not to work properly on the IIGS, though should not affect the Mac's operation. Most likely the circuit board in the A9M0106 receives the speed signal from a Mac and disables it, whereas on a IIGS, whatever that pin is used for is applied accordingly. Pina's detailing of the problem in Repair and Upgrade (page 193) "for 64K ROM diehards" is merely informational, probably in the event you don't have the proper ribbon cable. It is very easy to confuse what Pina is saying based on his writing style so I'm not surprised JDW mis-understood.

I suspect that the external disk drive is queried by the system for a disk at a regular interval when attached and for whatever reason the 800K drive does not return the proper answer on a 64K ROM Mac. I'll have a look at Inside Macintosh and see if I can confirm that. FYI, the original 800K drive (M0131) also accesses the disk (though it has no LED to flash) until a disk is inserted. However, without the HD20 INIT on a 64K ROM Mac it cannot be used. This is most likely why the older drives cannot be used in the A9M0106 external enclosures, at least with the IIGS. Though if the circuit board does not receive the speed signal from the Mac, it may not know what what kind of computer it is attached to, should that make a difference. Though since JDW cut those lines, obviously it would seem to make no difference on a Mac.

Lastly, the 800K drives are MFD-51W, MFD-51W-10 (HD20 INIT only), MFD-51W-03 (used in the A9M0106) and MFD-51W-23 which I have seen referenced as used in the IWM Mac SEs. Obviously the last incarnation, I would love to get my hands on a MFD-51W-23 to see if they were further upgraded to avoid the problem JDW is having with the disk access. Just to be clear, I have come across drives labeled MFD-51W ONLY which appear to behave identically to the MFD-51W-03 (without the HD20 INIT), yet can use either red or yellow ribbon cable. Perhaps this is the MFD-51W-23 and Sony had dropped the suffixes at some point. Otherwise, it is a the original 800K drive which Apple subsequently crippled to prevent use without the HD20 INIT. Either way, Pina in Dead Mac Scrolls only refers to these drives as MFD-51W which I suspect is a simplification as a result of the unpredictability of part numbers and their corresponding drives. I will at some point try using the this drive in the A9M0106 to see if it operates any differently.

 

[JDW]

First I would refer you to this if you have not read it: http://docs.info.apple.com/article.html?artnum=1605

Thank you for the link, but I believe I had posted that in the past on this site. But alas, that thread too was deleted in the server crash a few months ago! Nevertheless, I would have you know I own both types of cables (red stripe and yellow stripe). I tried those cables before and after cutting the wires I mention above. It does not solve the LED flashing issue.

Pina's Macintosh Repair & Upgrade book is... often unclear and contradictory to published Apple info... you really have to read it several times to understand why he's saying it. I'm afraid you mis-interpreted this to mean you had to physically cut wires on your drive.

You are correct about mistakes in Pina's books, but you are not correct in assuming I misunderstood. If you re-read my post above, you will see that I mention I had referenced sources other than Pina before making my decision to severe wires (which was done in such a way that I can easily connect them again). I tend not to trust any single source of technical information. I prefer to see the same or similar content in two or three places prior to my believing it.

it might be worth a look at the Apple IIGS 800K floppy controller pin-outs to see if there is a signal line that might be cut which would prevent the LED flashing and disk access.

I've cut and tried many different combinations of wires, but I the only combinations that stop the LED flashing are the same combinations that stop the drive itself from working.

Apple says specifically NOT to put the older drives in the A9M0106 external enclosure.

To be precise, you are referring to the second sentence of NOTE #3 at the URL you specified above. More specifically, that Apple tech page is just saying: "You should NEVER try to install the older MFD-51W or 51W-10 drive mechanisms in a PN# 661-0345 floppy drive enclosure. Only the MFD-51W-03 mechanism should be used inside a 661-0345 enclosure." Interstingly, the A9M0106 drive is not the same as the 661-0345. Nevertheless, my A9M0106 drive has the MFD-51W-03 drive mechanism inside it.

AS A HACK, you are using something that is not designed to be compatible with your system and therefore is likely to do lots of things that bothers you. I doubt cutting any cable will stop the problem without rendering the disk useless.

That is why I have not been complaining about Apple or the Macintosh in general. I merely discovered an anomaly and posted it here on this site (long ago, but all that has been wiped away in the server crash), in hopes that some other technically inclined soul, more technical and experienced than I, can possibly provide some insight that would lead me to a solution. Even if it requires some simply programming of a PIC MCU to stop the problem, I may be open to that. But I would first like to explore less involved options that may work. So far, no one has provided a solution. But that's not to say no one will. And thanks to the server crash on this site that wipe much of my experience away, the response to this problem has been "delayed."

I am thrilled you are helping to clarify the mis-information on the web. I am certainly not looking to take credit as discovering this, or certainly overshadow your accomplishments ... if anybody deserves the credit it's Larry Pina!

I simply try to do for others what I would want them to do to me. I also believe in the Biblical notion that "there is nothing new under the sun." No doubt, much of what we think we have invented as "new" has actually be thought of by someone else before (regardless of the fact they may have taken it to the grave with them). I therefore do not take "credit" as such, but simply mentioned my previous posts to you in an attempt to point out that I have, for quite some time, been thinking about the points you have suggested to me. But I too would like to formally credit Pina with his work. He was a very constructive and dedicated member of the Macintosh community for many years. May more such people rise up among us and keep the classic Mac community alive and kicking!

I will not state anything that I myself have not tested. That said, I must tell you that while this 800K drive works without the HD20 INIT, the actual 800K External Drive M0131, sold for the 512K & Mac Plus will NOT work.

I appreciate this insight. I've often wondered about it. But in not having an M0131 myself, I could never test such.

on a 64K ROM system, you CANNOT use HFS formatted anything without the HD20 INIT which will not load on a 128K. On a 512K, even with your drive, you must have the HD20 Init in order to write HFS formatted disks with a System 2.1 or later. System 2.0 and earlier will write MFS ONLY with or without the INIT.

Thank you for posting those clarifications.

your posts seem to indicate that you are limited to 400K without the HD20 Init. on your drive and that's how mis-information gets around.

I never mentioned any '400k limit without the INIT,' and I would take issue with insinuations that such is "mis-information." If a criticism is to be lodged against me, it would be more accurate to say that "some people could think 'such-and-such' because you did not say 'this or that.'" But I never intended my posts above to be 100% comprehensive, saying all that could be said on a given subject. Indeed, if I was able to do that, I should likely put it in print and begin sales on Amazon!

With that said, I appreciate your clarification on this point -- something which I was well aware of but did not clearly state in my post above.

I too look forward to new discoveries in classic Mac computing. It takes time to post those discoveries on the web, which is why we have times of relatively few posts here. But I would like to encourage those of you out there reading this to be diligent and make time to post your experiences. Posting what others have done is nice for those of us who have never read such articles or tips before. But to post your own first hand experience is far better, and it makes that information more real and more fun for yourself as well.

Thanks to everyone who has contributed to this thread. And a special thanks to Tom Lee for your hard work in putting together that excellent technical PDF for us!

 

[Mac128]

Apple says specifically NOT to put the older drives in the A9M0106 external enclosure.

To be precise, you are referring to the second sentence of NOTE #3 at the URL you specified above. More specifically, that Apple tech page is just saying: "You should NEVER try to install the older MFD-51W or 51W-10 drive mechanisms in a PN# 661-0345 floppy drive enclosure. Only the MFD-51W-03 mechanism should be used inside a 661-0345 enclosure." Interstingly, the A9M0106 drive is not the same as the 661-0345. Nevertheless, my A9M0106 drive has the MFD-51W-03 drive mechanism inside it.

Actually no, at the risk of calling another misunderstanding, that's not what the note says. Part #661-0345 is NOT a "floppy drive enclosure". It is in fact the drive mechanism inside the A9M0106 enclosure. MFD-51W-03 is the SONY part number and 661-0345 is the Apple part number for the sony drive mechanism. A9M0106 is the Macro part number for the entire assembled unit marketed as the 'Apple 3.5" Drive' which contains 661-0345, the Sony drive mechanism. So what you say below is actually correct but misleading. The A9M0106 is in fact NOT the same as the 661-0345. However, 661-0345 is the same as the MFD-51W-03 and is not an "enclosure" of any kind but a drive mechanism. So, what the note actually says in translation is: don't use Sony drives with part number MFD-51W or 51W-10, otherwise known as Apple part number 661-0305, inside the external drive with Apple part number A9M0106, otherwise known as the Apple 3.5" Drive, but ONLY use the Sony drive with part number MFD-51W-03, otherwise known as Apple part number 661-0345. Sorry for the elaborate explanation, but as I said before this is how misinformation gets started, through no fault of our own. Apple's site is the source of much misinformation itself, but in this case I have personally verified what they are saying, if however badly. So it makes perfect sense that your A9M0106 contains the MFD-51W-03 – it's supposed too!

You are correct about mistakes in Pina's books, but you are not correct in assuming I misunderstood. If you re-read my post above, you will see that I mention I had referenced sources other than Pina before making my decision to severe wires (which was done in such a way that I can easily connect them again). I tend not to trust any single source of technical information. I prefer to see the same or similar content in two or three places prior to my believing it.

Not to beat a dead horse ... but what other sources detail cutting the ribbon cable on an external drive to disable the speed control & voltage? Are you referring to Lee's article you linked to above? That also speaks solely of the internal cables, not external. In either case, the writing is ambiguous and could easily be mistaken to mean any drive connected via any method. While I have certainly not seen every source on the subject, those are the only three texts in which I have seen this problem explained and I have never seen a source that explicitly indicated the cutting of an external drive's wiring was necessary. Also, did you try to use the red & yellow ribbon cables inside the A9M0106, or on your internal drive? Out of curiosity what is the Sony part number for your internal 800K drive, is it also a 51W-03?

Also, please forgive me, I did not mean to insinuate you had intentionally provided misinformation at any time. Moreover, that lack of complete information is how misinformation originates. And certainly we are all guilty of it (including Pina and Lee)!

Cheers :beige:

 

[JDW]

your posts seem to indicate that you are limited to 400K without the HD20 Init on your drive...

Mac128, you've inspired me to be even more zealous about confirming things 100%. Tonight I did some checking, and it would appear that you are indeed "limited to 400k without the HD20 INIT." At least, you are if your 800k disk is formatted HFS. And despite what I've "read" on the net, I cannot get any of my 800k disks to format as MFS. You can read my report about formatting 400k & 800k disks in HFS/MFS.

My "guess" is that you would not be limited to 400k without the HD20 INIT if you could format an 800k disk MFS. The reason my Mac512 with 64k ROMs cannot see 800k disks without the HD20 INIT is because of the HFS formatting, I believe, not the physical size of the disk itself. But again, I need to create an MFS 800k disk to test this for sure. So if you have some insights to share in this regard, I'm all ears!

Thanks.

 

[tomlee59]

JDW and Mac128 -- thanks for providing such an incredibly detailed discussion about this issue. With your permission, I'd like to include a summary of your conclusions (with proper attribution, of course) in a future rev of the classic mac tech docs.

I continue to be amazed at the knowledge (and persistence) of the folks on this forum!

--Cheers,

Tom

 

[JDW]

Tom, I'm not one for taking credit. But if some of the dialog I've contributed on this site can assist you in bettering the classic Mac community, then I'm all for it. Please freely use whatever information I've posted as you see fit.

And once again, Tom, thank YOU for that outstanding technical document. A lot more work went into that than we've posted here, that's for certain. You are to be greatly commended for that excellent work! Your work actually inspired me to be more diligent about testing things on my old Macs and toying with hardware modifications. For that I am sincerely grateful to you.

 

[Mac128]

Dr. Lee, of course you may have my permission to use any of this info. That's why it's on a public forum. Like with most open source though, it's always good to provide links to the original (despite the fact they may disappear at some point since the internet is like the sands of the Sahara). But you know that, good citations help prevent future confusion from paraphrasing or interpretation which may have a bias or inferred interpretation not intended in the original.

That said, I've no doubt that would be a problem for you. I'll take this opportunity to thank you for all the invaluable help you have personally provided to me over the years troubleshooting my old Macs, not to mention your wonderful data sheet on the Mac Plus, also an invaluable document. In fact I'm the first to say way beyond the level of technical expertise I have with the Mac. Though I'm guilty of trying to hack the Mac in the past, I've since adopted the path you showed me, which is to preserve and embrace the limitations of these old workhorses.

As for the 800K MFS disk format, instead of being redundant, I too posted my responded on the HD20 discussion page. However, the short answer is I need to go back and document the exact steps I took rather than speculate and provide misinformation myself, as the procedure just "worked" for me and I remember thinking: ahh, good ole Larry Pina!

 

[Mac128]

I put this together last night. It is the pinout comparison table for the Macintosh Plus and Apple IIGS. Of note is that the Apple IIGS uses pin 4 & 16 to select the 3.5" drive or the 5.25" drive. Obviously this has to do with the circuit board between the disk and the external connector cable. Also note that pin 10 which provide the speed control signal on a Mac 400K drive and pin 9 which is normally disconnected on the 800K drive, are used for other purposes on the Apple IIGS. Again obviously all controlled by the circuit board. I would tell you, JDW to try to connect the external cable directly to the drive and bypass the internal ribbon cable connector, but I think it would simply pass through the speed control which the circuit board isolates from the 800K drive, unless needed. All-in-all this is a very sophisticated drive to allow it to work with so many different disk formats. As I postulated earlier, Apple would have been well aware of the flashing LED & drive access pending the insertion of a disk on a 512K Mac. Obviously they did not deem this a problem or they would have found a way to eliminate it. Which leads me to speculate as to whether they could have fixed it on the drive side at all, or given it only applied to the 512K (and to a lesser extent the 128K, though they don't officially support that configuration), they made a financial decision not to spend any more resources on it – in which case you may well be able to design a circuit to circumvent the LED flashing. If the former ... then the fix will have to be applied to the Macintosh side. JDW, like Dr. Lee I defer completely to you as a technical expert, I would not begin to try to understand how to construct such a circuit or where to begin to employ it. But if you figure it out, then I'm happy to follow instructions and build one myself. Hopefully this table will be of use to you in that end:

(pin number/Mac in black/AppleIIGS in red)

. 1 CGND Chassis ground GND ground reference

. 2 CGND Chassis ground GND ground reference

. 3 CGND Chassis ground GND ground reference

. 4 CGND Chassis ground 3.5DISK Apple 3.5 drive enable

. 5 -12V -12V -12 volts DC

. 6 +5V +5V +5 volts DC

. 7 +12V +12V +12 volts DC

. 8 +12V +12V +12 volts DC

. 9 N/C Not connected DRVEN drive enable

. 10 PWM Regulates speed of the drive WRPROT write protect

. 11 PH0 Control line to send commands to drive PH 0-3 stepper motor phases

. 12 PH1 Control line to send commands to drive PH 0-3 stepper motor phases

. 13 PH2 Control line to send commands to drive PH 0-3 stepper motor phases

. 14 PH3 Control line to send commands to drive PH 0-3 stepper motor phases

. 15 WrReq- Turns on the ability to write data to the drive WREQ write request

. 16 HdSel Control line to send commands to the drive HDSEL 3.5" drive head select

. 17 Enbl2- Enables the Rd line (else Rd is tristated) DRVEN drive enable

. 18 Rd Data actually read from the drive RDDATA read data

. 19 Wr Data actually written to the drive WRDATA write data

One final thought ... as I indicated earlier, the 51W-03 800K drive went through at least one more revision to the 51W-23. Given that the A9M0106 was introduced in September 1986 and was not discontinued until December 1992 for use with the IIGS, newer versions may contain the later drive model and the drive itself may have compensated for the access problem. But that is sheer speculation and presented as a variable to check. However, If I am correct and my plain 51W (no -ext.) drive is actually the final version (i.e. -23), then it is essentially the 51W-03 with the socket header pins disconnected for use exclusively as an internal Mac 800K drive (and would not have ever been used in the A9M0106). I suspect the red and yellow internal ribbon cable confusion may have become a headache for Apple at some point. Either way, such a drive may take care of the flashing LED problem. Either way I will try it with my drive when I have time. Good luck!

 

[tomlee59]

Gentlemen, I thank you both for your generosity. I will definitely follow Mac128's suggestion of providing links to the originals, precisely to moderate the errors of omission and commission he alludes to.

And please call me Tom!

 

[JDW]

Mac128, thank your for the technical pin-out. It will be very helpful. For now, I'd like to post another set of observations about the LED flashing issue, which I'd seen in the past and just confirmed in tests a few moments ago...

To recap... When connecting an A9M0106 external 800k floppy drive to a Mac512 with 64k ROMs, the LED flashes (and drive motor spins) once every few seconds, as shown in

(the video is about screen wobble, but ignore that and focus on the LED of the external drive).
Now, I also have an Apple HD20 serial 20MB external hard disk drive. If I connect my A9M0106 floppy drive to the HD20 (it doesn't matter of the HD20 is switch ON or OFF), and then connect my HD20 to the floppy port of my Mac512, there is no LED flash or drive motor access every few seconds when I switch on the Mac512. Yeah! However, you won't be able to use the A9M0106 drive in this case either -- if you put in a floppy of any size in the A9M0106, no LED will come on, and it will not boot. Also, if you put a boot disk in the 400k internal drive of the Mac512, the machine will boot, but the A9M0106 will remain dead unless you also load the HD20 init. Without the HD20 init, if you boot to the Finder and put a floppy into the A9M0106, it will not light the LED nor mount your disk. But if you have a 400k boot disk with HD20 init, part way through the boot process you will see the LED light up and the motor access on the A9M0106, and the A9M0106 will be useable from that point.

Of course, this means you cannot boot off the A9M0106 when it is connected to the Mac via the HD20. But if you connect the A9M0106 directly to the Mac, you will have the LED polling problem every few seconds, but you can boot off the A9M0106 (the motor will simply make a low pitched buzzing sound when accessing your disk, unless the HD20 init is loaded, in which case it will become quiet and a bit faster too.)

Hope this information is useful. No doubt you HD20 users out there have experienced this yourself if you've also used the HD20 with an external 800k floppy drive.

 

[Mac128]

As you wish, Tom it is!

Now that the little MFS 800K formatting issue is behind us, I was hoping you could help me understand what is basically a hardware issue, that somehow the 128K ROMs and HD20 INIT compensate for.

It seems to have some root in what JDW's problem is with his Apple 3.5" Drive and the initial topic of this forum.

What I'm referring to is the "PULSING" issue when using an internal 800K drive and ANY external drive, 400K or 800K, regardless of which internal ribbon cable (red or yellow stripe) is connected to the internal 800K drive.

With the 3.5 (A9M0106) drive, it continually access the disk until a disk is loaded, though the 400K external does not do this, nor does it happen when used with 128K ROMs.

Obviously both problems are a result of the 64K ROM's .Sony disk driver deficiency to recognize the attached 800K drives. Whereas the external A9M0106's goes away once a system loads (unlike JDW, a solution I'm fine with BTW), on a 64K ROM Mac the pulsing continues with an internal 800K unless the HD20 INIT also loads.

What I don't understand is what's causing it. The internal 800K by itself works fine, HD20 or not. But the minute you plug in an external drive, the pulsing starts. Is it some kind of feedback loop? If so, shouldn't there be a fix for this by just cutting some wires, or adding a resistor? How does the HD20 INIT & 128K ROMs resolve it?

Hopefully you can provide the answer, since installing an 800K drive inside a 128K is mostly impractical if you intend to use an external drive, unless you are deaf as the pulsing will drive you nuts!

 

[JDW]

...MFD-51W-23 which I have seen referenced as used in the IWM Mac SEs.

Mac128, what is your "reference" that mentions this "23" model number? I ask because I've Googled it and haven't come up with much of anything.

 

[Mac128]

Well, first you have to call it what Sony does, NOT Apple. I tell you it's a real miracle anybody put the right prat into anything back then ...

What Apple calls MFP-51W-xx, Sony calls MP-F51W-xx and to make matters worse, when you search the net sometimes you have to leave out the hyphens or sting all the numbers together or leave spaces instead and in different places.

However, Starting wth Tom Lee's own verification on the forum: http://68kmla.org/forums/viewtopic.php?p=12635&sid=b0be4fa639868d2a41f45b73549f4ce9

And then this: http://www.nehaia.dk/cm_archives/1997/01/970104.html

And this: http://home24.inet.tele.dk/ccadams/se/super.html

All of these indicate that it came out of a later Mac II or SE. The drive I have came out of a late model Plus. So by deduction, it makes sense it came after the -03 model.

But the thing that was invaluable is a parts list that describes the type of drive and the Sony part number and the OEM it was supplied for, which of course I can't find the link to now ... as soon as I do I'll post it.

 

[JDW]

Thanks for the links.

From reading through the thread in your first link, I found this photo of the bottom of a MP-51W-23 drive. If someone knows the way to decode these serial numbers, perhaps there is date information that could be useful in determining when these were made. Since many people have decoded the serials on old Macs to determine such dates, I don't think it should be impossible to decode these SONY serial codes.

And this company still sells the -23 drive at a tremendous discount of only $29! :

 

[Mac128]

This should prove helpful with older drives ...

http://www.rapid-tech.com/products/sony.htm

 

[JDW]

What you and I are both doing is a HACK. PERIOD. The 800K drives may well work with the 128K (and indeed Apple intended this from the beginning when the double sided drives became available, but their strategy changed when they created HFS), BUT once Apple changed to HFS, they made no attempt to make them compatible with the 64K ROMs without the HD20 INIT and HFS support. For whatever reason the A9M0106 and MFD-51W-03 drive doesn't care, possibly to enable compatibility with the Apple II. Notice Apple says specifically NOT to put the older drives in the A9M0106 external enclosure. Therefore, AS A HACK, you are using something that is not designed to be compatible with your system and therefore is likely to do lots of things that bothers you.

A kind soul recently emailed me a PDF of the original Apple documentation for the A9M0106 800k floppy drive. That same kind soul suggested I remove the URL from this post, which I have done (out of fear Apple would fly their lawyers to Europe and shutdown this site for posting Apple II manuals). So if you want the PDF, just PM me.

Anyway, once you have that PDF, scroll down to page vii. Apple states that the A9M0106 is fully compatible with not only a 512ke, not only ROM-upgraded 512k's, but also with stock Macintosh 512k machines (which have 64k ROMs).

The software requirements are shown on page 10.

So the A9M0106 800k floppy drive is fully compatible with my Mac 512k (and therefore not "a hack"). And yet, the flashing LED issue I reported earlier in this thread still exists. I don't see the flashing LED issue as something inherent only to my A9M0106 drive. No doubt it occurs when connecting any A9M0106 drive to any stock Mac512. And so, I will assume that this flashing LED issue, while not specifically mentioned in Apple's drive documentation, was a known issue at the time the drive was sold.

 

[Mac128]

Yes and I was that "kind soul". You'll note from that exact same quote I also wrote:

That said, certainly Apple must have known the A9M0106 worked without the HD20 with 64K ROMs (as well as the MFD-51W-03 drive). Since very little is known about the exact release dates and discontinuation of the external drives or the rational behind Apple's design, it has been assumed Apple intended the A9M0106 as a universal replacement for all of their previous 400K & 800K drives and as such, an original 128K/512K Mac which still needed a 400K drive could buy it as a replacement external with an eye toward upgrading in the future. If so, they must have also known the LED would flash and drive accessed until a system disk was inserted with or without the HD20 INIT ... All-in-all this is a very sophisticated drive to allow it to work with so many different disk formats. As I postulated earlier, Apple would have been well aware of the flashing LED & drive access pending the insertion of a disk on a 512K Mac. Obviously they did not deem this a problem or they would have found a way to eliminate it. Which leads me to speculate as to whether they could have fixed it on the drive side at all, or given it only applied to the 512K (and to a lesser extent the 128K, though they don't officially support that configuration), they made a financial decision not to spend any more resources on it – in which case you may well be able to design a circuit to circumvent the LED flashing.

Also in that manual you'll note on page 10 it also specifically states that the 512K must use the HD20 INIT with the A9M0106 as well as a minimum System 2.1 and Finder 5.1. It also states to ALWAYS start up from a 400K disk from the internal drive. Page 15 is emphatic about this point and encourages upgrading to an internal 800K drive.

So two things here:

1) you and I both know that this drive works with earlier systems and finders and can be used as a startup disk just fine and without the HD20 INIT. And

2) If we are using this drive in any other way than specified, it is a HACK.

Finally, clearly my earlier statement has been simmering on some minds. For that I apologize, but I would also take issue that what I said was taken somewhat out of context. By the time I said that, we had been discussing all kinds of things including pulsing of internal drives & formatting MFS 800K disks. I sent you the link to the manual because, you should have it as an owner of one and it helps clarify some things, in particular for me it helps clarify that Apple half-heartedly supported the drive. Had you owned the drive in 1986 when it was released and called Apple support about the disk access light, they would tell you it was known issue and would not affect the operation of the drive and then they would offer to help you order the 800K internal drive upgrade kit. The manual also clarifies the main thing I care about, which is that they do not specifically indicate it is incompatible with the 128K, which of course it is not. In the end the fact that Apple supports it for the stock 512K doesn't make it any less of a hack. It's just an Apple hack. The mere fact they place so many limitations on how it can be used is a dead giveaway. Either way, I am happy to get to the bottom of the issue and indeed, I am willing to admit when I am wrong, particularly when I am the one who continued to research the issue to better understand my own thoughts. But thanks for stealing my thunder and gloating about it!

Oh, one final thing about posting links to copyrighted material for the benefit of the community: this manual comes from what appears to be a Polish or Czech site so it might be hard for Apple to shut them down. But forums like these are crawled almost every night and well indexed for search engines for any corporate attorneys to review. If we want to keep information like this online, we might want to keep this type of link off the record and share privately. Just my two cents.

 

[JDW]

...in that manual you'll note on page 10 it also specifically states that the 512K must use the HD20 INIT with the A9M0106 as well as a minimum System 2.1 and Finder 5.1. It also states to ALWAYS start up from a 400K disk from the internal drive. Page 15 is emphatic about this point and encourages upgrading to an internal 800K drive.
So two things here:

1) you and I both know that this drive works with earlier systems and finders and can be used as a startup disk just fine and without the HD20 INIT. And

2) If we are using this drive in any other way than specified, it is a HACK.

You're talking about the software side in the above argument: when loading software off a disk. But my flashing LED issue is a hardware issue that occurs BEFORE any software is loaded. Hence, in regards to my LED flashing issue, the OS version or use of the HD20 INIT is irrelevant.

So basically what I posted above was about the hardware issue, not anything else we've spoken about in this thread pertaining to software issues. And in the sense that using an A9M0106 with a stock Mac512k is perfectly okay according to Apple's own A9M0106 documentation, such use "is not a hack" in my book (even if you consider it "an Apple hack.") If it was truly "a hack" as hacks are normally defined (performed by end users versus the manufacturer), then the LED flashing issue wouldn't be anything unusual. But since my use of the drive is not a hack insofar as Apple says the floppy drive can be used with a Mac 512 and makes no note of potential problems, I became curious as to why Apple would have overlooked this LED flashing issue. If they knew of it at the time of printing that manual, they still could have stated the floppy drive was compatible with a stock 512k but then add a note that "it is recommended to upgrade to 512ke ROMs" in such a case. But there is no such recommendation in that manual. That's all I was trying to say.

Had you owned the drive in 1986 when it was released and called Apple support about the disk access light, they would tell you it was known issue and would not affect the operation of the drive and then they would offer to help you order the 800K internal drive upgrade kit.

That's most likely true and is what I am going to assume here. Even so, the motor still spins (accesses) when the LED flashes. And the LED flashes every couple seconds, so clearly you wouldn't want this to continue for hours on end. But of course, you could also argue you wouldn't want to leave your Mac switched on for hours on end in such a condition anyway.

...we might want to keep this type of link off the record and share privately.

Post above edited. Link removed.

 

[Mac128]

In fact I'll bet Apple purposely enabled the disk access & LED to drive people nuts and force them to upgrade their 512Ks with the 800K internal drive upgrade kit once they had already purchased the drive. ;-)

If they knew of it at the time of printing that manual, they still could have stated the floppy drive was compatible with a stock 512k but then add a note that "it is recommended to upgrade to 512ke ROMs" in such a case. But there is no such recommendation in that manual. That's all I was trying to say.

Ah, but they do ... in Apple's own unique way. Page 15 is very clear, Apple wants you to upgrade your drive and ROMs. There is no way Apple did not know of the disk access problem if they ever plugged it into a 512K Mac and I find it hard to believe they would support it in writing without actually testing it. Also, this is not just a problem with the A9M0106, but also the M0131 800K External Disk Drive which had already been out for at least 9 months before, so Apple would have been well aware of that problem for anyone trying to use it with a stock 512K.

In fact I posted this early on in this thread as well:

and the 512K is listed as compatible: http://docs.info.apple.com/article.html?artnum=10268

and Apple makes no mention of any anomolies with the drive ... and as you know, these Knowledgebase articles tend to have been written after the products have been out for a while (and also known to contain lots of erroneous info). So the compatibility of the drive was never in question and the PDF manual is no revelation as far as that goes. But that doesn't make it any less of a hack, whether we are using it inappropriately or Apple put a band-aid on it and didn't make it fully compatible. When I said it was a hack, I meant in the sense that Apple didn't even try to make it fully compatible, or the problem that troubles you wouldn't exist and I said as much in what you quoted as well:

BUT once Apple changed to HFS, they made no attempt to make them compatible with the 64K ROMs without the HD20 INIT and HFS support ... you are using something that is not designed to be compatible with your system and therefore is likely to do lots of things that bothers you.

So all I was saying is that Apple never intended the drive to be fully compatible with 64K ROMs whether they officially supported it or not. I only cited the software argument because Apple places official restrictions on the drive which have nothing to do with its compatibility, making it a technical "hack".

Therefore, I will say publicly that yes JDW you are in fact right. But I am not wrong, either and I apologize for make such an inflammatory statement.

Hopefully at this point I think we agree, what Apple did here was to offer up a drive with a known issue with 64K ROMs and went ahead and marketed it for use with the stock 512K, but looked the other way and hoped nobody else noticed, because as you point out, nobody in their right mind would switch on their Mac and just leave it sitting there flashing a question mark for any length of time. So in the few seconds it took to load a disk, they gambled no one would be the wiser and if someon did call them on it, they would just play dumb. (Amazing how little seems to have changed in 21 years, just having gone through the MacBook battery recall myself). This goes to my original assertion that Apple did not support the 64K ROMs for any practical purposes following the discontinuation of the 512K (and this drive came out 6 months after that). I guess what I'm saying is I am not surprised Apple did this since it would be admitting their "hack" if they put it in writing. I think they just wanted to sell drives and figured 512K owners would eventually upgrade anyway.

Nevertheless I hope you are able to find a fix for this problem Apple clearly chose to ignore.

And by the way,I said exactly what I meant about Apple shutting down a website offering copyrighted material and I did not say they would "fly their lawyers to Europe" to shut down the site, in fact I said it was unlikely they could. However, I have been around long enough to have seen Apple shut down a lot of online sources that offered such copyrighted items, lest we forget the fantastic www.applerepairmanuals.com – I resent the implication that somehow the fact that Apple II is old means Apple won't defend their copyrights and that I am somehow overreacting. What I do remember is that as soon as applerepairmanuals.com started showing up in the usual forums, just as quickly they got shut down. Since Apple gave up support in 1998 for most of the products which manuals were hosted there, you'd think they wouldn't care. Wrong. We can start a new thread if this needs to be debated further ...

 

[Mac128]

Here's an interesting development.

http://farm3.static.flickr.com/2089/2181427305_1efa08245c_o.png

Apple states that the A9M0106 is fully compatible with not only a 512ke, not only ROM-upgraded 512k's, but also with stock Macintosh 512k machines (which have 64k ROMs).

What's interesting is that the Service manual specifically notes that the 512Ke must have upgraded ROMs, which is exactly what the 512Ke is, leading me to believe they mean the drive is not to be used with a stock 512K (64K ROMs), since they don't mention the plain Mac 512K. So on the one hand you have the original manual that says it is compatible with the 512K (w/software) and on the service manual that it is apparently not. Seems like Apple changed its mind ... probably because of all the customers complaining about the constant disk access until a disk is inserted ; -)

Then there's this:

http://farm3.static.flickr.com/2289/2182513964_f968874207_o.png

http://farm3.static.flickr.com/2151/2181726141_f8ef981a87_o.png

Which seems to indicate that it is compatible with ALL Macintosh CPUs. Revised 1990, perhaps Apple has forgotten about the 512K if not the 128K.