Format 800K MFS with 64K ROMs

[Mac128]

The only thing I can think for a clean S2.1/F5.0 HD20 v1.0 disk not working on your setup is that whatever system you have installed on your HD20 was formatted and setup with v1.1 tools and S3.2/F5.3 which is somehow incompatible with the older version, especially if you are using a more current system on your HD20 than 3.2/5.3.

As I have speculated, System 2.1 may be a patched MFS system that relies solely on the HD20 INIT to patch the system. I'd love to see a Hard Disk 20 manual to see how Apple implemented this for the user. Under that assumption System 3.0, then is a fully HFS aware system that by 3.2 (in a short 5 month span BTW) probably works somewhat differently. I need to compare all of these systems to confirm my theory though.

Curious to see what happens with the ResEdit HD20 INIT. At best, I can only hope it will mount the HD20 and allow you to see it on the desktop, but I would not expect the .Sony driver would hand off the system to it. Chances are, without the "TFS" resource, your Mac won't recognize the HFS format on the disk and ask you to initialize, in which case that would tell us, it sees the disk. Try three different hacks:

1. "TFS" & .Sony resources ONLY (may allow reading HFS without system handoff)

2. "Dispatch Kernel" & .Sony ONLY (who knows?)

3. .Sony only (should be MFS read only)

Something I am also curious about ... when you loaded System 2.1/Finder 4.1 with the normal HD20 INIT and then inserted a known HFS disk, did the extra pixel show up? I'm wondering if that's a feature of the Finder or the System.

 

[JDW]

when you loaded System 2.1/Finder 4.1 with the normal HD20 INIT and then inserted a known HFS disk, did the extra pixel show up?

No. The HFS "single pixel" does not show up when I use Finder 4.1 in conjunction with your System 2.1 (or System 2.0). So when I said, in my posts above, that I checked my formatted 800k disks for that pixel, I was implying that I had booted with a more modern system disk that will show that HFS pixel.

As to the ResEdit hacks, I will try the variations you suggest when I find the time over the next few days (hopefully today, if I can) and report back here.

And yes, my HD20 does have a System and Finder much more modern than the S2.1F4.1 disk you gave me. I am using Finder 6.0 and I think System 4.1 (I'll need to boot my Mac to confirm the System version). But again, this is more modern than the boot disk I was using. Nevertheless, I have always used two different 400k HD20 INIT boot disks without problem to boot from my HD20. One of those floppies has Finder 6.0 and System 4.1, while the other floppy has Finder 5.5 and System 4.1. So this shows that the boot floppy will still hand over control to the HD20 even if the boot floppies Finder is a bit older than the Finder on the HD20. As to the System being older, I will have to test this further and see what happens.

Thanks.

 

[JDW]

Okay, Mac128, here's my detailed test report using your Magic System 2.1 / Finder 4.1 disk and a patched HD20 INIT. Note that I put System 3.0 and Finder 5.1 on my HD20 to make the HD20 boot with your Magic floppy.

(1) Deleted "Dispatch Kernel" but left TFS & .Sony in the HD20 INIT via ResEdit. No "Disassembler installed" message inside the Welcome to Macintosh box, but I see the LED flash and disk motor access on my external 800k drive during boot. I can format 800k disks MFS! Yeah! But the HD20 won't boot with this disk. Instead the disk boots to the Finder, at which time the computer locks up hard, and the arrow cursor cannot be moved.

(2) Deleted "TFS" but left Dispatch Kernel & .Sony in the HD20 INIT via ResEdit. No "Disassembler installed" message inside the Welcome to Macintosh box, but I see the LED flash and disk motor access on my external 800k drive during boot. I can format 800k disks MFS! But the HD20 won't boot with this disk. Instead the disk boots to the Finder, at which time the computer asks me if I want to initialize the HD20 or Eject it. No crashes/lockups in this case, but of course, the HD20 won't boot nor is recognized at the Finder (most likely because its HFS formatted).

(3) Deleted "Dispatch Kernel" & "TFS" but left .Sony in the HD20 INIT via ResEdit. No "Disassembler installed" message inside the Welcome to Macintosh box, but I see the LED flash and disk motor access on my external 800k drive during boot. I can format 800k disks MFS! But the HD20 won't boot with this disk. Instead the disk boots to the Finder, at which time the computer locks up hard, and the arrow cursor cannot be moved.

And there you have it. So while it didn't give us a means of formatting the HD20 as MFS, it was an interesting set of tests. And originally, my HD20 wouldn't boot at all (the Welcome to Macintosh box would flicker and the computer would lock at that point). But before, I had System 4.1 and Finder 6.0 on the HD20. When I downgraded the HD20 to System 3.0 and Finder 4.1, I could make it boot using your Magic disk, so long as I had the unaltered HD20 INIT installed on the floppy.

 

[Mac128]

Okay, Mac128, here's my detailed test report using your Magic System 2.1 / Finder 4.1 disk and a patched HD20 INIT.

OK, keep in mind that 2.1/4.1 is not "magic" it's just 2.1/4.1 unmodified. I chose 2.1 because it is only about 3K bytes different than 2.0 (yet HFS "aware"), whereas 3.0 is significantly different (almost double the size, fonts notwithstanding). The modified HD20 INIT is the only "magic" element this time.

Interesting results and thank you. Your second test I do find encouraging. Obviously you don't want to initialize your HD20, but for someone with an HD20 that has nothing on it, I would be most interested to learn the results of clicking "initialize" instead of "eject". Perhaps my HD20 will magically begin working again one day!

You did try booting with an unaltered HD20 as well correct? I am somewhat surprised that a clean 2.1 & HD20 INIT did not at least "see" the HFS formatted drive as it does with an 800K HFS disk on my Mac, but perhaps the fact you had a system on your HD20 at all prevented the drive from simply mounting and instead kept locking up as it tried to hand-off the system and the hand-off may require the 5.0 Finder. I would certainly use the exact same system and Finder on your HD20 as the boot disk in any event for these tests. Verifying the clean system 2.1/5.0 HD20 v1.0 INIT compatibility with your current 4.1/6.0 system would be helpful too.

 

[JDW]

I would be most interested to learn the results of clicking "initialize" instead of "eject". Perhaps my HD20 will magically begin working again one day!

Clicking "initialize" in order to see if the HD20 is then formatted MFS... Yes, that would be an interesting test. But as I wrote in this post, it would be most practical to first partition the HD20 and then format one partition MFS. Of course, to do that, a programmer among us would need to compile the Nested Volume Manager code here. And if you read through that Nested Volume Manager article, you can see they talk about MFS formatting too. So that article itself lends evidence to the fact people have formatted their HD20's MFS. It just seems that you wouldn't want to format the entire drive as MFS, for reason I mentioned in my other post.

You did try booting with an unaltered HD20 as well correct?

My HD20 boots just fine off an unaltered boot floppy that has System 2.1 and Finder 4.1 or higher (I "altered" your original floppy to put Finder 4.1 on it). More specifically, if I used an unaltered HD20 INIT on your System 2.1 disk and with Finder 4.1 on it, it properly hands control over to the HD20 during boot, the floppy ejects, and the HD20 boots and runs just fine (so long as I have System 3.0 and Finder 5.1 on the HD20). But in my 3 test cases above, you can see that I had modified the HD20 INIT on the boot floppy. That's why, in all 3 of those cases, the HD20 did not boot. In other words, if you delete any resource in the HD20 INIT, the HD20 will not boot. So instead, in my 3 test cases above, the boot floppy did not eject -- it continued booting to the Finder. It was at that point that the system either crashed or gave me an "Initialize" dialog for the HD20.

Finally, keep in mind that if I put System 4.1 and Finder 6.0 on my HD20, even with a virgin HD20 INIT on your System 2.1 / Finder 4.1 floppy, the HD20 will not boot and instead the Welcome to Macintosh box will flicker and the computer will lock up at that point.

I am somewhat surprised that a clean 2.1 & HD20 INIT did not at least "see" the HFS formatted drive as it does with an 800K HFS disk on my Mac

Like I said, per your requests in posts earlier in this thread, I had to alter the System 2.1 disk you gave me. The 2 changes I made were: (1) put the HD20 INIT on it (and all my "test variations" of the HD20 INIT, one at a time) and (2) put Finder 4.1 on it. Once you put Finder 4.1 on your disk, it becomes "magic." Meaning, with Finder 4.1 on it, I can then format 800k disks as MFS. I could not do that simply by adding the HD20 INIT alone to your virgin disk. The reason is because the Finder version you have on your disk was too new. But after downgrading your Finder to version 4.1, it formats 800k disks as MFS.

I also found that sometimes I could mount an HFS formatted 800k floppy (with System 2.1 / Finder 4.1 / virgin HD20 INIT), but the HFS floppy's contents would not show up in the Finder (the window would be blank) -- but it didn't ask me to initialize the disk in such a case. Perhaps this unusual anomaly occurs because System 2.1 is HFS aware whereas Finder 4.1 is not.

I would certainly use the exact same system and Finder on your HD20 as the boot disk in any event for these tests. Verifying the clean system 2.1/5.0 HD20 v1.0 INIT compatibility with your current 4.1/6.0 system would be helpful too.

I did confirm that your virgin System 2.1 / Finder 5.0 disk would not boot my HD20 if my HD20 had System 4.1 and Finder 6.0 on it. However, I did not try to test my HD20 using your System 2.1 and Finder 5.0, nor did I try using your System 2.1 and Finder 4.1. But like I stated above, Finder 5.0 prevents me from making 800k MFS disks, so there's little value in me testing that case. However, testing System 2.1 and Finder 4.1 on my HD20, and then trying the S2.1F4.1 boot floppy with a virgin HD20 INIT may be an interesting test. If it works, it would show that Systems and Finders older than the version that originally shipped with the HD20 could in fact be used to boot the HD20.

 

[Mac128]

I did confirm that your virgin System 2.1 / Finder 5.0 disk would not boot my HD20 if my HD20 had System 4.1 and Finder 6.0 on it.

Thats what I was looking for, a litmus test! So what that means is the original HD20 startup disk will not work with older systems. I'll bet System 3.0 & Finder 5.1 (or maybe even 5.0) will work just fine with a newer system. I read an interesting article in MacTech that detailed the changes thoroughly and SYstem 3.0 and up really changed the System resources considerably.

Otherwise, I think we are starting to repeat ourselves! LOL At this point I am interested in the pure mechanics of how the HD20 INIT works and not so much the practicality of it. I think we have the MFS formatting dilemma behind us.

As for MFS partitioning, of course it works. I have an application called MacServe which was the original AppleTalk disk serving and network printer software dating back to the Lisa. Essentially that allowed you to partition an HD 20 with HFS & MFS volumes. And originally they were MFS only. I saw it explained somewhere that HFS folders are basically just disk partitions. Since my HD20 is currently not working, I have set this up on a ZIP 100 drive running System 3.2/F5.3 that boots the Mac. The key is, the drive must be formatted according to the manufacturer instructions. So the HD20 (like the ZIP) must be initialized HFS, then MacServe partitions the drive however you want.

I'm basically curious if the HD20 could be initialized completely MFS and therefore used with an MFS only system. I agree partitioning it would be the only practical way to use it.

However, testing System 2.1 and Finder 4.1 on my HD20, and then trying the S2.1F4.1 boot floppy with a virgin HD20 INIT may be an interesting test. If it works, it would show that Systems and Finders older than the version that originally shipped with the HD20 could in fact be used to boot the HD20.

I would certainly be interested in the results. And if using my ZIP 100 drive is any indication, entirely possible. As long as the Mac can see and understand the drive and there is a system on the drive that the Mac understands, then it shouldn't matter what version it is. However, as you pointed out Finder 4.1 is NOT HFS aware. I believe that the normal version of the HD20 INIT makes System 2.1 HFS aware, but does nothing for the Finder which is why the System can see HFS formatted disks, but cant write to them, or discern their contents & folders. That seems to be the Finder's job, to find the folder "partitions" or file structures. However, you wouldn't want to use such a system if it did work since you would royally screw up your data by writing files MFS onto an HFS formated disk. The only variable is whether something in the "hand-off" would prevent it from loading.

There is a lot of info on these pages of invaluable nature for working with and further investigating an 800K drive, HD20 and MFS/HFS Systems. However, the main goal of working with 800K MFS disks has been achieved by not one, but two and conceivably other methods. Clearly the HD20 is best formatted for practical use as an HFS drive and partitioned accordingly using existing software and other solutions. I will keep working on the MFS issue for the large volume access on a 128K as that is where my goal lies and report back, but until someone is ready to initialize an HD20 most of it will be theoretical.

 

[Mac128]

FYI, this seems to be a very odd entry in the Apple Knowledge Base:

http://docs.info.apple.com/article.html?artnum=8757

and seems to suggest something that is not supposed to be possible. It makes me wonder if an HD20 could be formatted on a Mac Plus with System 2.0/4.1, basically resulting in a 20MB MFS volume that could then be used with a 64K ROM Mac.

Otherwise, why have a tech note about it? I will test and report back.

 

[Mac128]

It works. The HD20 can be used with MFS. If only developers had know this back in 1985, it would have solved many problems with applications that took many months to become HFS compatible.

As of this writing, I've only successfully formatted the drive MFS using the stock System 2.0/Finder 4.1 on a 512Ke which obviously has the HD20 drivers built-in along with the 800K driver and HFS. Since the system doesn't know how to implement HFS, erasing the drive produces a 20MB MFS volume, which with limited testing seems to function perfectly. To double check this, I then booted with an HFS system which showed the appropriate pixel on the left-hand side of the System volume windows and no pixel on the HD 20 volume windows. Rebuilding the HD 20 desktop and also deleted any "virtual" folders. Using this drive with an installed system on a stock 64K ROM 512K with the standard HD20 startup disk, boots up normally, spitting the HD20 disk out and the drive running under its own system. If an HFS system is installed on the drive, after it loads the Mac it likewise reports the HD 20 volume as MFS, while correctly reporting other HFS disks as such. I would NOT run it this way, however.

While the HD 20 startup disk works with the HD 20 on a 512K, I haven't found an MFS system configuration that formats it correctly and I'm not sure why. Basically, it formats it with significantly less space (5MB less). Depending on the system, HFS, MFS or version that is used, it reports everything from 0K available, to 30MB. I suspect this is the same issue I experienced with using the same 800K floppy to format MFS & HFS in earlier tests. Some of those disks ended up showing 1.4MB available. I'll report back when I have time to do a low level format of the drive and then do a clean format from one of the "Magic" Systems discussed above.

Now I know JDW has indicated that there is little need for a 20MB MFS volume because of the organizational problems since all files reside on the root directory only and can't be truly nested directory style. I don't necessarily disagree. There is also another issue with the MFS Finder 4.1 which restricts the number of files on any one volume to 128 to 500 depending on the Mac. So unless you have some really big files, you won't even be able to use all 20MB. Also, the Finder responds more slowly the more files it has to manage. Ultimately you'll end up with a very sluggish system on an under utilized drive. The solution prior to HFS was to use disk partitioning, which also limited you to being able to mount a limited number of partition volumes at once. Unfortunately, this is a hack Apple never intended anyone to find out about and thus there is no partitioning software that I know of for this express purpose. I'll be posting some details about MacServe eventually which will partition an HD 20 with some limitations, but MacServe was designed to be an AppleTalk disk server, so it eats up a lot of RAM in the process of simply partitioning your hard disk.

And then there's the fact that the 64K ROM Mac is inherently an MFS environment which is best served by not using up your valuable RAM with HFS code. Unfortunately, the 128K has been restricted by Apple from ever loading the 800K disk drivers and HD 20, which would only take up a minor piece of the limited RAM (certainly no more than the hard drive drivers that were marketed for the 128K at the time).

Nevertheless, having used the HD 20 which is certainly slow on even a Mac Plus, I have decided that a 20MB flat filing system is preferable to the HFS nested one. Why? If you know the contents of your 20MB disk intimately, it's easy to go straight to the folder and find what you need. But heaven help you if you forget where you put something as I do all the time. Even an HD 20 with a dozen folders, each with one or two sub-folders can take what seems like an eternity to open and search all of them. As you know, there is no search function built into the old finder and you are limited as to how you can view the files on a disk. With a flat filing system under MFS, this problem goes away. You may have an enormous list of files all on the root directory, but at least you can sort them alphabetically, date, size and kind to quickly find what you are looking for. I would actually be willing to bet money on this that I could find a file on an MFS-based HD 20 faster than someone using the HFS version who has to dig through folders.

There's more to research here, but obviously it's a great alternative to have.

 

[Mac128]

In addition to the entry I found about the HD20 above, this one seems to suggest Apple knew all about formatting MFS 800K disks, though with a Plus. Certainly I cannot imagine why Apple would ever endorse using 2.0/4.1 with 128K ROMs.

http://docs.info.apple.com/article.html?artnum=1788

 

[JDW]

...the Finder responds more slowly the more files it has to manage.

That is certainly true, even on an HFS formatted drive like my HD20. I have quite a large number of files stored on it, and it takes a LONG time to display a window in the Finder for the first time after cold boot.

Mac128, many thanks for your outstanding report. You clearly spent considerable time investigating this AND in typing it in for all to read! Hopefully the owner's of this 68kMLA forum are regularly backing up server data (and then confirming the backups are good) so we don't lose all this important information ever again!

I personally look forward to hearing more about your successes in partitioning the HD20, with some MFS and some HFS partitions and how well they interact with each other. Certainly, if the software you have takes up too much RAM to do its job, then it's not a practical solution. In such an event, I can only hope that the Nested Volume Manager would be an alternative partitioner. But it would take a programmer among us to compile the code given in that MacTech article. It looks like all the code is there in that article, but I myself am not sure how to piece it all together and compile it into a standalone app.

Anyway, once again, thank you Mac128 for your dedication to the classic Mac community. No doubt we have many other classic Mac lovers out there who actively tinker with their machines in technical ways; but sadly, only a select few "white knights" like Mac128 make time to sit down and report about those effects. Kudos, Mac128!

 

[Mac128]

UPDATE:

In order to format the Hard Disk 20 using a stock Mac 512K with 64K ROMs, you'll need to use the "Magic" System 2.0/4.1 as described above, with the HD20 INIT and erase the HD20 as usual. This will reformat the disk as MFS. But here's the catch, you can't actually use this or any MFS only system with an MFS formatted HD20 with 64K ROMs, because Finder 4.1 and earlier doesn't know how to handle a 20MB volume, even though it has no problem formatting it. On a 512Ke, the information the Finder needs to handle that same 20MB is already in the ROM, so Finder 4.1 and earlier work just fine in decoding it. Evidently the RAM-based HFS leaves a few things out.

So, in order to use this spacious 20MB MFS disk with 64K ROMs, you'll need to use an HFS aware system, which will treat the HD20 the same way it treats a normal 400K disk, as MFS, reading and writing MFS. That means Finder 5.0 or above. You just won't be able to format the HD20 as MFS using these systems, they will only format HFS. Then again, you only need to format it once.

In a quick test I discovered that MacServe will happily format an HD20 MFS formatted disk using its own partition map. Once the HD20 has been formatted with MacServe, you can use any System you like, including System 2.0/Finder 4.1. Evidently MacServe DOES know how to handle 20MB of MFS storage and lets the earlier Finder know how to deal with it. Whatever the case it works.

One further note about MacServe as I continue to experiment with it, using an HFS aware System with MacServe will also let you format the HD20 as MFS and then sub-partition the MFS volume with both HFS and MFS volume partitions. Using Finder 4.1 or earlier, will only let you partition one way, MFS. I haven't had the time really to work with anything much, but this configuration seems solid. I'll write this all up eventually and put it out there for others to experiment with as well.

 

[wthww]

Hate tro bring up this old post, but I'm going to try and get that nested volume manager together for you

EDIT: on a further note, This may be an issue because I can't seem to find a copy of Mega-whatever C that he uses, and the code is.. incomplete in some places. I'll look at it further when my eyes arent so blurry.

 

[Mac128]

UPDATE ON DRIVE COMPATIBILITY:

I have now tested the following 3.5" External Drives with a 64K ROMs:

Apple UniDisk 3.5" – MFD-51W mechanism

Introduced in September 1985 with the HD20

This drive works with the Liron interface bypassed without the HD20 INIT.

This drive interestingly will not work with the 800K Ext. Drive cable (with or without the HD20 INIT).

However, it will work with the 400K Ext. Drive cable as well without the HD20 INIT.

Macintosh 800K External Drive – MFD-51W-10 mechanism

Introduced January 1986 with the Mac Plus

This drive does not work with any cable without the HD20 INIT.

Apple 3.5" Drive – MFD-51W-03 mechanism

Introduced September 1986 with the IIGS

This drive works with any cable but the 800K Ext. Drive cable and the UniDisk cable causes continuos eject, without the HD20 INIT.

(The FDHD Superdrive MFD-75W-01G also works like an 800K Apple 3.5" Drive as well)

What's interesting here is that the UniDisk for the Apple II was released well before the 800K Drive was available for the Mac and could be used with or without the HD20 INIT with 64K ROMs, but the internal Liron interface card disabled it from otherwise working with the Mac. The newer 800K Ext. Drive did not have an interface card, so it seems Apple deliberately disabled an updated version of the Sony drive (-10) and changed something about the DB-19 cable to further disable it, in case the UniDisk drive-type mechanism (which is otherwise compatible) ended up in it, so it would still only function with the HD20 INIT. I'm sure in part, this kept anyone from attempting to continue to use MFS with the 800K drives even though it is easily possible -- particularly where the 128K was concerned which could not use HFS. What better reason to upgrade to a Mac Plus?