Macintosh Hard Disk 20

[MinerAl]

In a way I'm surprised that Apple dropped hardware support for the HD20 so quickly... ...what about existing customers moving to new machines?

The HD 20, the external Floppy Port, Floppy Drives themselves, ADB, Serial and SCSI in one fell swoop, Firewire 400, Firewire 800, the 30-pin iDevice connector...

Apple will introduce new technologies and then kill them (sometimes just one generation later) when existing customers "still need" them. This is their S.O.P. They want to sell you a new sprocket to go with your new widget, not a new widget that'll work with your old sprockets.

 

[Charlieman]

In a way I'm surprised that Apple dropped hardware support for the HD20 so quickly...

I'm not surprised. Apple heavily pushed the Mac Plus upgrade for the Mac 128K/512K in 1988/89 so that they could drop customer support. After promotional discounts, the upgrade was cheap by Apple standards. At the same time, Apple would have dropped support for the HD20.

In reality, "dropping support" meant that they did not test it with newer models. Some models would have been untested for practical reasons (eg the standard Macintosh II does not have an external floppy drive port). Definition of support needs clarification too. Some models will officially boot from the HD20 (ie the Mac ROM was tested to work) and others will read/write (ie boot support was not tested, but may be present in ROM).

Another consideration is that the HD20 has a passthrough floppy port to which a floppy drive or HD20 can be added. That's one more layer of complication for testing...

 

[Blinkenlightz]

The HD 20, the external Floppy Port, Floppy Drives themselves, ADB, Serial and SCSI in one fell swoop, Firewire 400, Firewire 800, the 30-pin iDevice connector...

Entirely true - maybe this one strikes me as different because it's an "artificial" drop. Had support stopped when the external floppy connector did, that would have been "normal" (regardless of whether external floppy drives might still have been useful at the time). But dropping code out of ROM for a device where the hardware requirements are still met, to me that's a different story.

As an analog, for example: it might be comparable to if, when Apple started selling USB iPods, they dropped the ability to connect a FireWire model to any Mac built after a certain time -- despite having the FW400 port present and having OS and application support still there. It seems arbitrary.

That said, I'm not intimately familiar with the "secret sauce" that enabled the HD20 to function over the floppy port. Is it truly only some code in ROM? As I understand, the HD20 isn't emulating a huge floppy disk, it really is treated differently but happens to use the same physical connector.

In reality, "dropping support" meant that they did not test it with newer models.....

Now that, to me, is entirely reasonable. If that were the case though, I suppose it would have been found to work, at least in part, on some "unsupported" models.

I might test for myself, now I'm intrigued...

 

[uniserver]

do you have an HD20 buddy?

 

[Blinkenlightz]

I have a working HD20, and thanks to you, working SE/30 and IIsi. So I can at least try those out, see what response I get from them, if any.

 

[uniserver]

ok cool!

yeah let us know what you find!

looks like the INIT is 28k…. i would think that would fit in the Dougg3's ROM???!??!?!?!?!

if not, then i am sure there is something useless maybe we could trim outta there to make room for this 28k init.

or maybe the SWIM its self wont support the HD20….!?! either way man i would really like to find out!

awesome man… getting some use outta that SE/30 that one was quite a pain in my rear Glad its working good for you man!

 

[techknight]

ok cool!yeah let us know what you find!

looks like the INIT is 28k…. i would think that would fit in the Dougg3's ROM???!??!?!?!?!

if not, then i am sure there is something useless maybe we could trim outta there to make room for this 28k init.

or maybe the SWIM its self wont support the HD20….!?! either way man i would really like to find out!

awesome man… getting some use outta that SE/30 that one was quite a pain in my rear Glad its working good for you man!

SWIM works. My SE had a SWIM in it, and it booted that HD20.

 

[Macdrone]

The 30 doesn't boot with the 20 but I have not tried the init. Same with the II's

 

[bear]

There's a table of what is and isn't supported with the HD20, in the Apple Guide to the Macintosh Family Hardware.

Note: The Apple Hard Disk 20 is an earlier, non-SCSI drive designed for use on classic Macintosh models that have no SCSI port. Although you can connect a Hard Disk 20 to the external SWIM connector of the Macintosh SE/30 and Macintosh IIcx computers, those computers do not have drivers for the Hard Disk 20 in ROM. Neither the Macintosh SE/30 nor the Macintosh IIcx can be started up from a Hard Disk 20. (The Macintosh IIci does have the requisite driver and can start up from a Hard Disk 20.)

Table 2-1 Non-SCSI disk drives used by Macintosh computers
=============================================================================================================
Computer                    Interface  Internal disk drives  External disk drives         Start up from HD20?
-------------------------------------------------------------------------------------------------------------
Macintosh 128K,             IWM        One 400 KB            400 KB
Macintosh 512k
Macintosh 512K enhanced,    IWM        One 800 KB            400 KB, 800 KB, or HD 20     Yes
Macintosh Plus
Macintosh SE                IWM        One or two 800 KB     400 KB, 800 KB, or HD 20     Yes
Macintosh SE FDHD           SWIM       One or two FDHD       800 KB, FDHD, or HD 20       Yes
Macintosh SE/30             SWIM       One FDHD              800 KB, FDHD, or HD 20       No
Macintosh Portable          SWIM       One or two FDHD       800 KB, FDHD, or HD 20       Yes
Macintosh II                IWM        One or two 800 KB     None
Macintosh IIx               SWIM       One or two FDHD       None
Macintosh IIcx              SWIM       One FDHD              800 KB, FDHD, or HD 20       No
Macintosh IIci              SWIM       One FDHD              800 KB, FDHD, or HD 20       Yes
Macintosh IIfx              SWIM       One or two FDHD       None                         No

 

[uniserver]

yeah we need to try the INIT.. on those machines in question.

if they work then we need to try and get that init in one of dougg3's ROMS !!!!

 

[Blinkenlightz]

Preliminary test results -

SE/30, System 7.0.1: No activity whatsoever. HD20 completely ignored at boot-up and after boot. Tested floppy port with an external 800K drive, the port is fine.

IIsi, Mac OS 7.6: No attempt to boot from HD20, booted from internal HDD. Immediately when Finder loaded, started a desktop rebuild on the HD20. Afterwards, was able to browse the HD20 and copy a file from HD20 to internal HDD.

 

[uniserver]

on iisi, go to start up disk, chose hd20 and reboot, then see if it boots?

 

[NJRoadfan]

The HD20 INIT is both the driver and the HFS File system driver. If you want "built in" support on a 128k and 512k, just swap in the Macintosh Plus ROMs. As an added bonus, you get 800k drive support.

 

[uniserver]

yeah but then the purists get their panties in a bunch.

the floppy emu should take care for the init… then eject… then emulate a HD20, with a 1gig image!

now that sounds fantastic!

 

[bear]

I never found much "official" info on the topic, but the HD20 does not work at all on the 128k, INIT or no. There just isn't enough memory available.

edit: On further reflection I suppose it is at least theoretically possible that a Plus ROM swap would solve that problem.

 

[unity]

The HD20 INIT is both the driver and the HFS File system driver. If you want "built in" support on a 128k and 512k, just swap in the Macintosh Plus ROMs. As an added bonus, you get 800k drive support.

It may have been my particular board, but on one 128k board I tried Plus ROMs and it would not work. Checkerboard screen. ROMs were tested just fine. Don't quote me though, I have not tried other ROMs yet. It is something I want to do when I have time.

 

[uniserver]

I'v tried plus roms in a 128k,

with different boards in differen instances.. and it always worked… its just STRANGE having a 128Ke!!!

lol

the INIT is 28k.

http://www.mac512.com/macwebpages/hd20.htm

ya i dont get it… this website says this:

The HD20 cannot be used with a Macintosh 128K, the Macintosh 512K can use it once you boot up with the HD20 INIT from a diskette.

but then it says this:

Download the HD20 INIT (28K file)- This lets your old Macintosh 128K or 512K use 800K disks and the HD20 hard disk.

So yeah i don't get it. I guess all there is to do test it first hand.

 

[Blinkenlightz]

on iisi, go to start up disk, chose hd20 and reboot, then see if it boots?

Done! The IIsi attempts to boot off the HD20. Doesn't get very far, because the HD20 has System 6.0 which doesn't support the IIsi. But it reads, says Welcome to Macintosh, then a polite suggestion to get a newer System and be sure to install support for the IIsi.

Under OS 7.6 I copied some software from the HD20 to the internal disk, and the application runs fine -- so I can be reasonably sure that data copied in that direction is OK. However, I've seen some references to "partial" HD20 support on newer Macs only meant to copy data from, not to, the HD20. I don't really feel like borking a filesystem tonight...

Aside from me feeling a bit risky since HD20s don't grow on trees, the IIsi seems perfectly happy exchanging bits with the HD20.

 

[uniserver]

alright lets add the IIsi to the list!

next we should try a SE/30 with a dougg3 rom.

IIcx

SE FDHD

 

[Macdrone]

SE FDHD work without init. Although accelerator is in it.