Twiggy 128K prototype, again.

[Strimkind]

There seems to be a lot of discussion on the subject whether the owners have attempted to boot it. I messaged him on ebay wondering if he had tried to use the unit or boot it in any fashion.

I see you have an interesting item here. Does the twiggy drive work? Have you been able to get it to boot from the external floppy port?
What I am really interested in is if the unit can see the twiggy disk when its booted.

Here is his response:

Hi, yes I have actually tried some of this experimentation. It would seem that the Twiggy Mac willnot boot from any 400k disk, but it does seem to want to reed a disk when inserted. I get a sad

mac icon, the error code indicates invalid system software. The ROM's may be designed to accept

only a particular pre-release version of the Mac OS, such as v0.6, which I do not have. I have seen

this in other prototypes from Apple, where they will only use 1 particular version of the Mac OS,

to prevent the machine fro being useful to the outside world after the product is released.

The mac will not read Lisa-formatted disks, the file system is completely different.

Found that piece of trivia to be interesting. I am still one for seeing someone get the unit working and how it works using the twiggy drive in the Mac OS

 

[Macintosh128k]

Isn't though the pinouts of the internal cable different between the sony and the twiggy?

So you couldn't expect to just plug in a 400kb external drive into the rear port

 

[Mk.558]

Hi, yes I have actually tried some of this experimentation. It would seem that the Twiggy Mac willnot boot from any 400k disk, but it does seem to want to reed a disk when inserted. I get a sad

mac icon, the error code indicates invalid system software. The ROM's may be designed to accept

only a particular pre-release version of the Mac OS, such as v0.6, which I do not have. I have seen

this in other prototypes from Apple, where they will only use 1 particular version of the Mac OS,

to prevent the machine fro being useful to the outside world after the product is released.

The mac will not read Lisa-formatted disks, the file system is completely different.

Would you be able to ask him if it will work with a Sony 400K? (I doubt few of those are in circulation, let alone work).

Interesting. so if we can't get v.6, then it really is a expensive non-working museum non-interactive relic.

 

[Dennis Nedry]

Dumping the ROM would be the best place to start. Running the ROM in mini vmac could give you some clues, especially if you can reproduce the non-booting behavior. You could try to figure out what the ROM doesn't like about the Mac OS, then modify the Mac OS.

This machine is simple enough to be hacked into working with its original ROM if the motivation / funding is present.

 

[Strimkind]

Would you be able to ask him if it will work with a Sony 400K? (I doubt few of those are in circulation, let alone work).

Interesting. so if we can't get v.6, then it really is a expensive non-working museum non-interactive relic.

I didn't get to asking about the Sony 400k, but I did direct him to a known source of 0.0-1.0 beta System Software that he could attempt to load on the unit.

 

[mcdermd]

No way! [Andy Hertzfeld is] part of the MacPantheon and there's no way I'd ever so so bold as to try to get in touch with that gang!

I know how you feel. I had quite a start when I figured out Steve Capps is one of my company's customers (onedoto.com). He was a pretty normal guy within our support emails, though.

 

[Mk.558]

Would you be able to ask him if it will work with a Sony 400K? (I doubt few of those are in circulation, let alone work).

Interesting. so if we can't get v.6, then it really is a expensive non-working museum non-interactive relic.

I didn't get to asking about the Sony 400k, but I did direct him to a known source of 0.0-1.0 beta System Software that he could attempt to load on the unit.

Well based on what he said about the 128K/T not being able to load Lisa formatted floppies, that means the only way to even get started is use a disk imaging application on the Lisa and write the 0.6 System onto a twiggy disk.

As I am not versed in Lisa operations (never even seen one in person) I couldn't tell how to do it.

 

[Strimkind]

Its possible that it may be able to load the 'new' OS (pre 1.0) by an external 400k drive that could have been imaged by software in System 7.

Still, I wish the guy good luck to get the unit booting. If it works, I am sure he will be able to get his $100k asking price.

 

[uniserver]

one more i saw from the cool video posted

The Macintosh is pretty fun to use, even to do a spreadsheet just like in the video,

Twiggy drive comment,

its big

its loud

its slow

and above all that, the twiggy seems it was unreliable...

the 400k (3 1/2) floppy was a MUCH better choice,

 

[Mac128]

Yes. About the only thing Twiggy had going for it was that it could hold over 800K of data compared to the standard 140K Disk II, or 360K DD.

Funny thing is, that 3.5" disk became a huge marketing tool for the Mac ("fits in your shirt pocket") which was rejected by Jobs initially until the 11th hour.

I'll say again, I seriously doubt a Sony 400K drive would even function on this Mac. Remember the Disk II is incompatible with the Mac pinouts. I seriously doubt the 400K external would be compatible with a port intended for an external Twiggy drive. Assuming it would electrically function, the odds of a Sony driver existing in a ROM this early when the 400K drive was still being developed in secret (known only to a few engineers at Apple), are pretty low. Remember, Jobs scrutinized everything that went into the Mac design, and caught every attempt by the engineers to sneak in stuff he didn't want. And he did not want the Sony drive, which required a number of modifications to work with the Mac at all. So even in the unlikely event that they did sneak the driver into this ROM, the driver would most likely not be compatible with the heavily modified production drive. In fact, there was a minor change made to the stepper motor of the 400K drive halfway through its production run which required a revision to the original 64K ROM, without which it would not function (you cannot use a late model 400K drive with an early model 128K). And that was during the 128Ks lifespan!!

 

[Strimkind]

I think its still worth finding out. Its possible that the 400k may work if the prototype has a IWM on the logic board. If a few developers were testing the 400k around the time this prototype was manufactured, its possible that their work may have made its way to this machine. The external port and disk controller may have been modified to accept an external 400k drive.

 

[Trash80toHP_Mini]

I understand why the drive's internal cable pinout may have been different for the TD, but why would the external FDD port be so as well?

 

[Gorgonops]

The "skin" is one of the more interesting features of the TwiggyMac to me from an engineering standpoint. It's obviously an afterthought/bugfix, or it should have been designed into the MacTwiggy chassis...

Just for clarification, regarding the whole "Skin" terminology, when I said "working-and-skinned Twiggy prototypes" I wasn't referring to anything specifically regarding shielding for the Twiggy mechanism, but to Twiggy-equipped Macintosh prototypes fitted with a full covering of case plastics, IE, "skins". Pretty much from the moment the unit in question became the subject of discussion Trash has been very stubbornly clinging to this idea that "TwiggyMacs" never actually existed, IE, that Apple engineers were never able to make the Twiggy drive work well enough to run the machine at all, let alone well enough to actually be able to slap some units together with pre-release plastics and show them to developers. (The fact that Apple shipped somewhere between 5,000 and 10,000 *working* Twiggy Lisas doesn't seem to count in the equation) He's actually gone so far to claim that every sighting of a TwiggyMac in early Apple publicity photos is a fake job, and that the authors of the Folklore.org website (among others who were directly involved in the project) "have their timelines wrong" regarding when the Sony 3.5 inch drive was adopted despite the fact everyone agreeing that it was an "11th hour" change. I would hope that the photos of TwiggyMacs apparently being used by Microsoft engineers would be enough to finally torpedo this notion, but I suppose they could also have been in on the vast conspiracy.

(Really, it's not either/or here. The fact that some features of the Twiggy-slotted protoype case/plastics suggest that a prototype assembled from them would probably suffer from overheating problems doesn't mean that prototypes assembled from those parts didn't exist and were not used during the software and hardware development process. Ever since the beginning of time every product shipped by a corporation is a flawed compromise between marketing, engineering, manufacturing, and financial priorities. Crazy Steve's fights with his engineers might of been particularly knuckleheaded at times, but I seriously doubt that a prototype Macintosh which could double as an Eazy-Bake oven is even in the top ten list of engineering flops the computer industry has turned out over the years.)

Regarding the metal "skin" on the Twiggy mechanism itself, there's absolutely nothing interesting about that, in the sense that it's a totally standard computer-industry solution to the problem of shielding a drive from the CRT. I've disassembled several all-in-one computers before and found similar aluminum boxes surrounding the disk drives; an Osborne One, which is unusual for a portable computer in that is sports two *full size drives* on either side of its CRT, has an almost identical shroud around each one. Here is a picture.

As to pinouts, why exactly *would* the Twiggy drive necessarily have a different pinout from the Sony drive? The photos of Twiggy drives show a 20-ish pin connector, and remember that Apple's version of the 3.5 inch drive was *completely customized* by Apple and inherits several Twiggy features, including PWM speed control, which are not in "normal" 3.5 floppies. Drivers are another story, of course. According a page about the Twiggy on the Lisa One a Fileware drive had two sides with approximately 50 tracks per side (that's a guess, I haven't found a genuine reference saying how many usable tracks the stated "62.5 TPI" resulted in) for a total of 871Kb of usable space on 100-ish tracks. The same reference says that Twiggy disks spun at between 218 to 320 RPM, which only a little over half as fast as 3.5 inch drive in the shipping Mac spun, and remember that the Sony drive holds either 400Kb in 80 tracks or 800Kb in 160 tracks (double-sided). So... the obvious conclusion is that the data rate is probably about the same but the Twiggy holds more data per track than the Sony, and thus their geometry is very different. Thus if follows that unless the Mac ROM contains some mechanism for detecting drive type and adjusting the expected geometry appropriately if the ROM in this Mac supports the Twiggy it's probably not going to have any idea what to do with a Sony drive, even if it's electrically compatible. Now, I wouldn't rule out the Mac having some ability to do drive detection; the section of "Inside Macintosh" discussing the drive sense codes shows that there are several "unused" sense combinations so if the Twiggy drive were able to return a different code for some query than the Sony and the Mac were able to check for it on bootup then the system could well work with either... but if the code for that ever existed it may of been removed from *shipping* versions of the Mac ROM.

The "gotchya" regarding this *particular* Mac that makes it even tougher to wheedle out is that apparently the "blinking disk" icon it displays when powered on is a picture of the Sony disk, not a Twiggy. Assuming one takes the origin story behind this Mac at face value, IE, it was sent to a sculptor as the model for a reward and wasn't intended to be a working unit, the most parsimonious explanation for the anomaly is that this unit was snatched off a software developer's desk, where it was being used with a prototype external 3.5 inch disk drive and had been fitted with the ROMs to boot from said drive in addition to/instead of its internal Twiggy. It's very possible said prototype drive wasn't completely compatible with later drives so... generating a disk for this machine may well be non-trivial.

 

[Trash80toHP_Mini]

I've never said, IIRC, that the twiggy drive NEVER worked at all, just never satisfactorily. The abysmal production yield figures were something I brought up at the very beginning. However, if the MacTwiggy mechanism had never worked at all, even SJ wouldn't have insisted upon using the clunker for so long! That makes no sense at all.

I have VERY STUBBORNLY claimed that there's no proof or even much reason to think that this particular TwiggyMac was ever a functional prototype in its current state. The 3.5" System Search Icon lends some credibility my theory that this thing was slapped together from leftovers at the Texaco facility when they were cleaning out developmental detritus. If it was sent to a sculptor as a reward, it may have been considered a non-functional showpiece originally and remains so to this day.

The aluminum box is interesting, and makes the AIO Mac a cleverly compartmented MiniAIO as opposed to the standard Lisa and AIO Trash 80 designs of the day. Looking at the 5.25" Floppy slot as an additional convection cooling outlet, the box itself as an air dam and producing a chimney effect up and across the AB toward the vents in the rear seems an elegant feature of the original design. Yes, my first thought was that it was an afterthought/bugfix, but upon examination of the new pictures on the auction listing, I had better second thoughts about its effectiveness and intent.

 

[Mac128]

Gorgonops, I'm sure you can set me straight on this, as much of what I'm saying about the electrical compatibility of the Twiggy vs. the Sony drive is based on my peripheral knowledge of planned Fileware implementation. The drive was supposed to replace Disk II and Disk III drives. Apple had adopted a uniform 19 pin connector for all drive peripherals, though the Disk II & /// are electrically incompatible with the Mac 19 pin connector. Also my understanding is that the Twiggy drive was internally connected in the Lisa via an essentially Parallel interface, whereas the Mac external interface is essentially serial. I presume the Fileware drives included with the Apple II & /// would have had a new custom interface which no doubt would have been incompatible with the Disk II & /// drives ... Or would it (and if they were compatible with legacy drives, then wouldn't that mean they were incompatible with the production Mac)? Now perhaps the Twiggy interface had already undergone the custom interface for the Mac, or perhaps the Mac was to debut the new interface for the FileWare drives and it was esentially the surviving 19 pin Mac floppy port. In which case the Sony drive was adapted to that. I simply don't know, and readily admit my understanding of Apple's floppy drive implementation may well be flawed.

More interesting to me now is that the floppy drive icon is indeed the 3.5" one, which guarantees that a Sony driver is in ROM. But as you point out, possibly not one compatible with the final drive considering what we know about the minor update during its production run. That said, the production ROM contains at least one unexplained driver, which is almost certainly for the Widget drive, almost certainly originally intended to ship in the HD20. So it's entirely possible, either that driver, or one of the others contained the code to recognize the Twiggy drive, if not in the production ROM at least in this build. Either way, I still go back to the fact that the Mac used a different file system, so without the Lisa software program used to format a Twiggy disk for the Mac, I seriously doubt a standard Twiggy formatted disk even with a compatible Mac OS on it would boot this Mac. But assuming there was some electrical incompatibility, I would not assume that it has been resolved here ... more likely the Sony drive was adapted to any legacy port at this stage of their respective development.

 

[Dog Cow]

Someone should find out when this Twiggy Mac was sent to the sculptor. Sometime in 1983, but we need a month.

 

[Dennis Nedry]

That said, the production ROM contains at least one unexplained driver, which is almost certainly for the Widget drive, almost certainly originally intended to ship in the HD20.

O.M.G.

We should figure out if we can exploit that driver instead of directly replicating the HD 20. That could potentially take away the need to boot from a floppy. Such an emulated hard drive may even have luck booting this bizarre-o Twiggy Mac.

 

[Trash80toHP_Mini]

Has anyone looked into the possibility that this is a late model 128k ProtoBoard and will boot from a standard external FDD?

I know Apple doesn't give away ice in the winter, but why give a non-functional computer as a gift? :

Unhook the Twiggy Ribbon and boot it as a standard 128k from an external Sony FDD? :?:

Sorry if it's been covered already . . . it was just a fleeting thought.

 

[Gorgonops]

Gorgonops, I'm sure you can set me straight on this, as much of what I'm saying about the electrical compatibility of the Twiggy vs. the Sony drive is based on my peripheral knowledge of planned Fileware implementation...

So... here's what I *believe* would count as "corrections"... I've referenced some documents like the Lisa FAQ at sunder.net, "Inside Macintosh", and an old IWM data sheet among others, but some of this is going from memory so it may not be perfect.

1: The reference to "widget" driver was discussed a while ago in one of our long threads about alternate ways to add mass storage to an original Macintosh. It's a red herring. That driver is in the "soft" version of the 64K Mac ROM that was loaded on Lisa 2s/"Macintosh XLs" when they were emulating a Mac. It's not in the "real" Mac ROM.

2: "Parallel vs. Serial": The IWM chip was designed with the Fileware drive in mind (the part predates 3.5 inch floppy drives by several years) and was used in the Lisa. (The IWM supports two modes of operation for the "control lines" present on the 19 pin external connector; there's the "Mac Way" where the lines are used to communicate semi-intelligently with the control registers on a Mac drive, and it also supports using the lines to generate raw stepper-motor control signals compatible with a Disk ][-style drive. If Fileware for the Apple II/Apple /// had ever become a shipping product I imagine both modes would be available on the associated controller.) The main difference between the Lisa and the Macintosh is in the Lisa drive I/O was handled by an embedded 2Mhz 6504-based computer not the main CPU, but that computer lived on the I/O board in the main card cage and not on the drives. The drives themselves are still "dumb"(-ish), like the Mac's drive. It was the Lisa's Widget and Profile hard drives that connected via parallel-(ish) ports.

There is one interesting thing, however: There were two versions of the Lisa 2, the 2/5 and the 2/10 (when you converted an original Twiggy Lisa to a Lisa 2 it became a 2/5), and the two systems had different I/O boards. This is covered in a section of the Lisa FAQ. In order to work with the 20 pin Mac-style floppy drive which was used after the conversion Lisa 2/5s (or former Lisa 1s) required a "Lite Adapter" be present in the card cage assembly to covert the *26 pin* Lisa Twiggy floppy connector. The adapter *mostly* remaps the pins but in addition it generates a 3.5-inch compatible PWM speed control signal in place of the Twiggy-appropriate signal. I had noticed from photos/video footage of a Lisa 1 that the drive cables *did* appear to be wider than a Mac's drive connector cable, and this is why....

HOWEVER, if you look at the photos of the Twiggy mechanism inside the prototype Mac it appears that is only has 20 wires, and the circuit board on the drive appears to be different compared to the Lisa version of the mechanism. So... this seems to be solid evidence that this prototype is using genuine intended-for-the-Macintosh parts rather than being fraudulently thrown together using a Lisa 1 Fileware drive and a Twiggy faceplate. Whether the use of the 20 pin connector indicates that the drive is directly compatible with the 3.5 inch drive is another question; the PWM signals are obviously incompatible between a *Lisa* Twiggy and a Sony drive, but since the Mac Twiggy uses a different circuit board all bets are off. Even if the two are electrically compatible if the board is fitted with the wrong ROM for the Twiggy drive (or the ROM is for the Twiggy drive and an externally-connected 3.5 inch drive is connected, for that matter) the drive that doesn't match the ROM might be spinning at the wrong speed to work properly even if you had an appropriately formatted system disk inserted in it.

More interesting to me now is that the floppy drive icon is indeed the 3.5" one, which guarantees that a Sony driver is in ROM. But as you point out, possibly not one compatible with the final drive considering what we know about the minor update during its production run.

So, I've been thinking about the floppy drive icon question and one possibility has occurred to me:

There undoubtedly was a transition period in which both Twiggy and Sony Macs were kicking around the labs. The Mac-adapted Sony drives were probably in short supply for at least a month or two, during which it would of been impractical to suspend all other work on the OS while the bugs were being worked out of them. One of the aspects of the Mac OS which is very clear from looking at the documentation (and from reading Folklore.org) is that the RAM-loaded part of the OS and the ROM are very tightly intertwined, and until the "gold release" date both were being updated on a regular basis as bugs fixed in one part required a change in the other part. (And as a result, changes that touched the ROMs would require all the software developers to immediately install a fresh set of EPROMS in their development machines.) The floppy driver in the Mac ROM is fairly self-contained and for normal use (IE, not formatting a disk or something) abstracts a floppy into appearing as a linear block device. (The vMac and BasiliskII developers leverage this property by patching out the floppy driver and replacing it with a disk image driver for emulation purposes.) What if for a certain period of time there were *two sets* of development ROMs being passed around the labs, one for Sony prototypes and one for Twiggys, and at a certain point the "blinking disk" icon was replaced with a picture of the Sony disk but disk driver remained Twiggy compatible for the developer machines that needed it? That would nicely explain why this prototype can't boot from an externally-connected 3.5 inch drive. It *may* be able to boot from the Twiggy, but generating the disk for it may be well-neigh impossible. A dump of its ROM would probably reveal the truth if someone knowledgeable enough were to isolate the disk driver and compare it with the shipping version.

(I suppose in principle if one *were* able to extract a Twiggy-driver from the ROM of this system one could go about generating a boot disk for it by connecting the Twiggy mechanism to something like a Mac Plus with a hard disk, loading a custom init that replaces the ROM disk driver with the Twiggy version, and using a custom formatter program to generate an appropriate disk to which a pre-release System version that might be compatible with the rest of the ROM could be copied to.)

I know Apple doesn't give away ice in the winter, but why give a non-functional computer as a gift? :

The computer was not a *gift*. The story is that it was sent to a sculptor to use as a model for a medal that was going to be given to members of the Mac development team. Supposedly the sculptor finished the job but Apple never requested he send the computer back to them so he kept it. Assuming the story is true your idea that this machine was "assembled from protoparts" specifically for this task doesn't make any sense; why would they go through the trouble to "assemble" a computer that doesn't even need to work when they could just grab one, regardless of condition, that looks enough like a Mac to serve the purpose? (If they were actually wasting the time putting something together why not just send him an empty chassis with case plastics screwed to it?) It makes a lot more sense that they either snatched this off someone's desk (to be replaced with a new Sony-equipped unit) or out of a storage room/loading dock/garbage bin where obsolete Twiggy units from internal developers /shipped back from places like Microsoft were piling up. For all we know this machine could be the very one sitting under a stack of papers in one of those pictures linked earlier, rendered obsolete by a Sony-drive model shipped to Redmond the previous week.

 

[uniserver]

good info!