kamath@reed.UUCP (Sean Kamath) (11/11/86)
In article <8083B5U@PSUVM> B5U@PSUVM.BITNET writes: > >In article <557@sdcc18.ucsd.EDU>, ee161abt@sdcc18.ucsd.EDU (Grobbins) says: > >> >>The IWM is also in the Mac, as memory serves, so it's not a design >>for the IIc/e/GS. And Woz wasn't on the Mac team. >> >>Grobbins. > As far as I can find, it is NOT in the Mac, and, if you think about it, why >would it be? The disk drive set up in the II series and the Mac are completely >different (can someone verify/disclaim this, as I know not much about the >innards ofmy Mac +). Oh, dear sir, yes, I open them every day, and I tell you there is indeed a space marked IWM with a little chip there. If you have ever used something like copy // mac you will see a menu with the option "Chang header bytes" with the default set to: D5 AA 96!!! Yes!!!! In fact, the Mac disks are indeed VERY VERY much like the Disk ]['s. WHy throw away all that knowledge. The unidisk 3.5 is the one that has evolved more. It interfaces with the protocal converter, but the addressing scheme is still the same! Read a book on software protection on the make. Most of it is straight out of Apple ][ books. ________________________________________________________________________________ Sean Kamath UUCP: {masscomp, decvax, allegra, psu-cs, ucbcad, ucbvax, purdue, hplabs, hp-pcd, sequent, uw-beaver, ihnp4, cbosgd, gatech, nsc-pdc}!tektronix!reed!kamath CSNET: reed!kamath@Tektronix.CSNET BITNET: reed!kamath@Berkeley.BITNET ARPA: tektronix!reed!kamath@Berkeley reed!kamath@hplabs DECNET: RHEA::DECWRL::"decvax!tektronix!reed!kamath" US Snail: Box 395 Reed College, Portland, OR 97202 (503) 239-7458 These are not the fastest or best paths, just the easiest to use. I hope they work. (Most notably the US Snail Service :-)
ee161aba@sdcc18.ucsd.EDU (David L. Smith) (11/12/86)
>>The IWM is also in the Mac, as memory serves, so it's not a design >>for the IIc/e/GS. And Woz wasn't on the Mac team. > First, the IWM was introduced in the //c, and according to my roomate, an >Apple II owner and follower for six years, that was its original use. It was >supposed to be used in the //x, and it is now in the IIGS. > As far as I can find, it is NOT in the Mac, and, if you think about it, why Yes and no. The IWM was created for the IIe/IIc but it's also in the Mac. It is an intergrated version of Woz's original disk controller for the II, doing GCR encoding on a disk drive. It allows for data encoding with almost no hardware and we all know that if Apple can avoid an extra chip (no matter how overworked the poor processor is) they will. That's why it's in the Mac. (And you were wondering why your drives are so slow:-)) Dave ======= David L. Smith SCUD {ihnp4, ucbvax}!sdcsvax!sdcc18!ee161aba
B5U@PSUVM.BITNET (11/12/86)
Bob,
Thanks for the info. I had asked my roomate (an Apple owner from 1980 and a
senior EE) and my friend/software source (Mac owner since its release and an
employee at the University's micro support center) about it, and what I posted
was based on that. However, knowing that they (and I) are fallible, I asked for
people who knew better to followup and clear the air. Thankfully, there are
people like you that can do so in a friendly manner. Sitting on my reader is
some major flames to reply to. I dislike replies like this; I am NOT a
computer expert and did not claim to be one, that is why I asked my question.
When it comes to the drives, not only are the Apple and Mac drives similar,
but now I hear that IBM is using the same format on their 3.5s, although they
hold 720k, not 800k (MS-DOS?).
Anymatter, thanks for the info, and if you have someting to point ot on the
Mac, let me know.
BTW, I received this letter on 11/12/86, yet it shows a mail date of 10/28.
I thought the reason we used Email was because it was faster :-) (seriously,
is there a reason it took that long?)
-------
==============================================================================
George A. Brownfield
Aerospace Engineering '87
The Pennsylvania State University
Bitnet: GAB @PSUECLA
UUCP: {akgua,allegra,cbosgd,ihnp4}!psuvax1!psuvm.bitnet!b5u
"Intellegence is getting more money for doing less work."
=========================================================================hansen%cs.uiowa.edu@RELAY.CS.NET (Kurt Hansen) (11/14/86)
The IWM is in the Mac! Also, the drives are similar enough to make it possible to read/write unidisk (//) format on the Mac drives and vice versa. I have seen products which claim to read back and forth already. Writing is about as hard a problem as breaking copy protection schemes, so it is slower to come out. Once Apple had such a design (the IWM), it only makes sense to use it in all their computers, (financial sense and compatibility sense). By the way, I've heard that the Macintosh line is now out-selling the IBM PC-AT line by almost two-to-one (in terms of market share). A hard blow has been struck for Apple-kind! A comment (while I'm at it) on the //x of the future. It is now possible to build a machine (with a 65816, a 68020, and a 80386) which would run software from Apple //, Macintosh, and MS-DOS families. (wow!) However, what would be the advantage? Perfect compatibility would be elusive, the machine would be expensive (at least in the present and next couple of years), and would be a massive pain to service and support, since dealers would need to handle all three lines on one machine. I see two advantages to offset all that: 1) being able to have just one machine (multiply expanded though it would be for most of us), and 2) massive choice of software and extras. Personally I don't see a market for such a machine until it can be priced at current Mac / //gs / PC XT levels. Businesses typically stay in one product family, so there goes the high end. I think it will be awhile, with my guess at the retail of such a machine being in the $5000 range, at least, and fully configured well over $10,000. Kurt
hyman@ICS.UCI.EDU (Glenn Hyman) (11/21/86)
You will find that the 800k drive for the mac will work as a replacement for the unidisk 3.5 but not the other way around