System 4.1 and HD20 INIT

[napabar]

Is the HD20 INIT needed with System 4.1 and a stock Mac 512k? I know the HD20 INIT shipped with System 3.x, but seems to be missing from the 4.1 installer script, even though there is a stock Mac 512k selection.

I've been having gyounk over at www.mac512.com do some testing for me. He said that System 4.1 was unstable and froze with the HD20 INIT, but when he removed it, it was stable and worked correctly.

Was just wondering if the features of this HD20 INIT were either built into the System in 4.1, or simply not compatible.

 

[JDW]

Is the HD20 INIT needed with System 4.1 and a stock Mac 512k?

No it is not needed if all you have is a truly stock 512k with 64k ROMs and only the internal 400k floppy drive. (And it is not needed if you have a 512ke, which has the primary code of the HD20 INIT built into its 128k ROMs.)

But I have a serial HD20 hard drive external to my 512k, and so I have use for the HD20 INIT. I also have an external 800k drive for which I want HFS support, which is another reason to use the HD20 INIT.

I also have confirmed in the past that the HD20 INIT does in fact work fine with System 4.1 and various Finder versions:

viewtopic.php?p=54726#p54726

Indeed, S4.1 and F6.0 is the highest System/Finder combination you can use on a stock 512k with 64k ROMs.

So why are you experiencing problems with your HD20 INIT and S4.1? Perhaps because either the HD20 INIT or the System file you are using (or maybe even the Finder file) are corrupt. Because as I said, I can get the HD20 INIT to work without problem with System file 4.1 and Finder versions all the way up to 6.0. Try download S4.1, the HD20 INIT and a Finder file from another source and then give that a go. Make sure you have them on an MFS formatted 400k floppy too. Then let us know the result of your test.

 

[Mac128]

Oh yes you did extensive tests JDW. You da man!

As Eric Rasmussen's site alludes, System 3.2 was considered at the time the max system for stock 512K macs. The mere fact that Apple began distributing only on 800K disks commencing with System 4.0, suggests that they expected anyone upgrading to that system on a 512K Mac to have already installed the 128K ROM and 800K drive upgrades (and therefore not need the HD20 INIT). Indeed to support the 512K and 512Ke on subsequent AppleTalk releases, Apple offered special Systems 3.3 and 3.4 with Finder 5.4 & 5.5, and 6.1 respectively, simultaneously with the release of Systems 4.0 & 4.1, and 6.1 – long after the System software was no longer supported on the stock 64K 512K. So I am not surprised the HD20 INIT was not part of the 4.0 installer. If you were going to install it on a stock 512K, you would have to first copy it to a 400K drive and copy the HD20 INIT to it in order to start up from it and access your HD20 to upgrade it, so Apple assumed you already had it.

Also, there were two versions of the HD20 INIT. v.1.0 is not fully compatible with System 3.2/Finder 5.3 and up, which coincided with HD20 INIT v.1.1. Not sure which version gyounk offered on his site or is testing with. I am more impressed that you are getting gyounk to respond to you. I have rarely gotten much substantiative responses from him, and he never clarified how he was able to get a stock 512K to run 6.0.8, per this link http://www.mac512.com/macwebpages/qamac128.htm despite the failure of JDW's well documented steps to do it - so not sure how reliable his tests for you are either.

But JDW definitely confirmed that the HD20 INIT is fully compatible with System 4.1 and in my experience is simply ignored if incompatible with a particular system.

 

[napabar]

I gave gyounk the disk to test out EasyShare on, since I don't have a Mac 512k right now. He's been very helpful in this endeavor, but both of us have run into problems. I'm running various versions of Mini vMac, and he's got the real thing, but we see different errors.

I guess the best thing for me to do is have a few other people see if they can get EasyShare to work on a stock Mac 512k. It's supposed to work with any Mac running System 3.2 and Finder 5.1. In my testing with Mini vMac, the EasyShare extension wouldn't load on System 3.2, or 3.3, but loaded fine of System 4.1 (using a Mac Plus version of Mini vMac). On the Mac 512k version, with the 64k ROM, it crashed at startup. gyounk was able to get it to load, but had other problems after the fact.

Can you two give this a whirl? It would be quite a find for the community if we could get a Mac 512k to act as a AppleShare compatible server.

https://public.me.com/nilesmitchell

 

[Mac128]

napabar, I'm not set up to test anything on a stock 512K right now, but I can tell you that Mini vMac is incompatible with the HD20 INIT. You did not mention that before. As near as Paul Pratt and I can figure, the HD20 INIT is making some kind of call for the real disk drive, causing the system to crash since the emulated driver does not know what to do with it. This is unlikely to be fixed as Paul rightly asserts, the 128K ROM solves any problem one might need the HD20 INIT to handle.

Not entirely sure what EasyShare has to do with the HD20 INIT, though. Is it a requirement of Easy Share?

 

[napabar]

Yeah, I noticed that HD20 INIT bug too on Mini vMac, irregardless of the EasyShare extension being there.

The reason I included it in the boot disk I gave gyounk is because AppleShare doesn't seem to mount shared MFS floppies through EasyShare. AppleShare mounts shared 800k floppies just fine, through EasyShare. So, if we are to get this working on a 512k, it would need the HD20 INIT and an external 800k floppy or HD20 to actually share anything.

Mac128, go ahead and try it on the 128! The read me file says "any Mac running System 3.2 and Finder 5.1" and that techinaclly includes the 128, but the memory requirements make it unlikely....but why not try it? :beige:

 

[Mac128]

napabar, I'm totally lost now. Does Easy Share require AppleShare? And it seems to also require HFS. If that's the case, then no it will not work on a 128K. The 128K will not load the HD20 INIT, nor will it recognize HFS disks. AppleShare will also not run on a 128K as it requires HFS.

However, if you only have 400K drives on your 512K, once you startup from a 400K MFS floppy with the HD20 INIT, you can then switch over to a 400K HFS formatted disk, or use one in an external 400K drive. Theoretically you should be able to switch over to the system on an HFS formatted 400K disk, even though you can't startup from it. Since the HD20 INIT is loaded into RAM, I'm not sure it actually needs to be in the System Folder of your EasyShare disk. EasyShare and AppleShare should then have no problems writing to the HFS formatted 400K disk, assuming they will recognize a 400K volume.

One other note, there are problems with the HD20 INIT code in that it's not completely compatible with some programs because it isn't actually the same as the HFS code in the 128K ROM. Therefore, it may not work with Easy Share. This was a problem with a number of early file sharing systems during the transition to HFS, prior to AppleShare. AppleShare did not arrive until 1987, by which time, it assumed native HFS. This is in part no doubt why the 512K AppleShare client is limited, compared to the Plus and other clients, and cannot be run as an AppleShare server, RAM considerations aside.

 

[napabar]

No, it doesn't require it. When I was speaking of AppleShare, I was speaking of the client Mac that was connecting to another Mac running EasyShare.

I agree, even if it loaded on the 128K, it wouldn't do you any good, since you can't share a MFS disk.

I have a sinking feeling this is going to require the 128K ROM, or a Mac 512Ke at minimum. That's OK, because I know of no other way to make a stock 512Ke a file server, so it's still a big find.