storkel@rudist.shell.com (S. Storkel) (10/05/89)
I was just looking at some of the product brochures for the new Macintosh Portable. Everything sounded great until I read the following paragraph: Processor Direct Slot (PDS) * The PDS is a high-performance slot connected to the microprocessor bus that will support one expansion card. (Note: The PDS is not compatible with the SE, SE/30, or NuBus expansion slots.) Maybe I'm being short-sighted here, but it seems incredibly stupid for Apple to have four totally incompatible interface slots. Only IBM would do something this stupid. It would seem to me that the smart thing to do would be to make ONE type of interface slot that would be the same across the entire Macintosh family. What happened? Did the interface guys get bored with three totally incompatible interfaces and decide to design a fourth just so the engineers at other companies would have something new to do? Why couldn't someone have designed things so that there were at most three types of interfaces (best bet: SE/30 and Mac Portable sharing the same type of interface). Sure it would have been a little bit more complicated, but I think the payoffs would have been well worth the effort. Where am I missing the boat? -- Scott Storkel Disclaimer: The opinions expressed above do not represent those of Shell Development Company, BLUware, Rice University, Apple Computer, or any other organization.
shiffman%basselope@Sun.COM (Hank Shiffman) (10/05/89)
In article <STORKEL.89Oct4144438@rudist.shell.com> storkel@rudist.shell.com (S. Storkel) writes: >Why couldn't someone >have designed things so that there were at most three types of >interfaces (best bet: SE/30 and Mac Portable sharing the same type >of interface). Sure it would have been a little bit more complicated, >but I think the payoffs would have been well worth the effort. Where >am I missing the boat? At a guess, I'd say you're assuming a level of processor compatibility between the 68000 and 68020/30 that doesn't exist. There are a lot of extra pins on the PDS for the SE/30 that don't exist on the SE. They're there because the SE has a 16 bit data path and the SE/30 has a 32 bit path. The Portable, like the SE, has a 16 bit path. So to be compatible with the SE/30 it would need a bunch of extra logic to take the 32 bit wide data coming in from the bus and ship it to the processor in two clock cycles, reversing the process for data going the other way. As to why the SE and the Portable can't use the same bus, there may be a number of reasons relating to the difference in clock rate, bus communication with the other slots in the Portable, power or cooling requirements or some other aspect of the Portable's architecture which make the simple approach taken on the SE unacceptable here. Finally, there may have been packaging problems involved in making the same size and shape space available inside the Portable as in the SE or SE/30. Any combination of these might have required the Portable to use yet another incompatible slot design. -- Hank Shiffman (415) 336-4658 Marketing Technical Specialist Software Engineering Technologies ...!sun!shiffman Sun Microsystems, Inc. shiffman@Sun.com
fiddler%concertina@Sun.COM (Steve Hix) (10/05/89)
In article <STORKEL.89Oct4144438@rudist.shell.com>, storkel@rudist.shell.com (S. Storkel) writes: > > I was just looking at some of the product brochures for the new > Macintosh Portable. Everything sounded great until I read the > following paragraph: > > Processor Direct Slot (PDS) > * The PDS is a high-performance slot connected to the > microprocessor bus that will support one expansion > card. (Note: The PDS is not compatible with the SE, > SE/30, or NuBus expansion slots.) > > Maybe I'm being short-sighted here, but it seems incredibly stupid > for Apple to have four totally incompatible interface slots. It does have some drawbacks... > Only > IBM would do something this stupid. Oh, I don't know. Some other companies would do the same or worse. > It would seem to me that the > smart thing to do would be to make ONE type of interface slot that > would be the same across the entire Macintosh family. This leaves you with either an LCD (lowest-common-denominator) slot, or be locked into a suboptimal design when you finally get to the point where you can use the nifty expansion features. > What happened? > Did the interface guys get bored with three totally incompatible > interfaces and decide to design a fourth just so the engineers at > other companies would have something new to do? Why couldn't someone > have designed things so that there were at most three types of > interfaces (best bet: SE/30 and Mac Portable sharing the same type > of interface). Sure it would have been a little bit more complicated, > but I think the payoffs would have been well worth the effort. Where > am I missing the boat? The Portable has *severe* power-usage constraints...also, with a 68C000 (or whatever the alphabet soup is) onboard, a lot of the the SEx's requirements are superfluous. There may be some problems with available space onboard, too. ------------ "...I was to learn later in life that we tend to meet any new situation by reorganizing: and a wonderful method it can be for creating the illusion of progress, while producing confusion, inefficiency and demoralization." - Petronius Arbiter, 210 B.C.
jnh@ecemwl.ncsu.edu (Joseph N. Hall) (10/05/89)
In article <STORKEL.89Oct4144438@rudist.shell.com> storkel@rudist.shell.com (S. Storkel) writes: > >Maybe I'm being short-sighted here, but it seems incredibly stupid >for Apple to have four totally incompatible interface slots. Only ... The Direct Slots are faster than NuBus, and less trouble in many respects to design cards for. I wouldn't mind having a fast Mac with a cache slot, a PDS, AND several NuBus slots ... each has its own advantages and disadvantages. v v sssss|| joseph hall || 4116 Brewster Drive v v s s || jnh@ecemwl.ncsu.edu (Internet) || Raleigh, NC 27606 v sss || SP Software/CAD Tool Developer, Mac Hacker and Keyboardist -----------|| Disclaimer: NCSU may not share my views, but is welcome to.
macman@wpi.wpi.edu (Christopher Silverberg) (10/05/89)
In article <STORKEL.89Oct4144438@rudist.shell.com> storkel@rudist.shell.com (S. Storkel) writes: >Maybe I'm being short-sighted here, but it seems incredibly stupid >for Apple to have four totally incompatible interface slots. Only >IBM would do something this stupid. It would seem to me that the >smart thing to do would be to make ONE type of interface slot that >would be the same across the entire Macintosh family. What happened? Well, i think the thing here is when you are dealing with computers, you want to allow for the best, or largest slots for expansion (ie height) So, if you restrict all of the Macs, or even just the SE/30 to such a small expansion slot, then you're limiting the expandability of the SE/30. It really isn't a big deal to have different slot types... granted, it would be nice, but you have to take each computer into account, and decide what is best for that particular machine. If a companie is distributing a quality product, they'll make versions for each computer, at little expense to the consumer. -- ============================================================================== (.) (.) | Chris Silverberg, WPI Box 719 | BBS Sysop: Main Street U.S.A u | USENET: macman@wpi.wpi.edu | 2400 baud - (508) 832-7725 \___/ | BITNET: macman@wpi.bitnet | Fido: 322/575 - Red Ryder Host
c8s-an@franny.Berkeley.EDU (Alex Lau) (10/05/89)
In article <STORKEL.89Oct4144438@rudist.shell.com> storkel@rudist.shell.com (S. Storkel) writes: >Maybe I'm being short-sighted here, but it seems incredibly stupid >for Apple to have four totally incompatible interface slots. Only >IBM would do something this stupid. It would seem to me that the >smart thing to do would be to make ONE type of interface slot that >would be the same across the entire Macintosh family. What happened? >Did the interface guys get bored with three totally incompatible >interfaces and decide to design a fourth just so the engineers at >other companies would have something new to do? Why couldn't someone >have designed things so that there were at most three types of >interfaces (best bet: SE/30 and Mac Portable sharing the same type >of interface). Sure it would have been a little bit more complicated, >but I think the payoffs would have been well worth the effort. Where >am I missing the boat? The SE/30 and Mac Portable can't have the same Processor Direct Slot type, because the SE/30 uses a 68030 chip, while the Portable uses a 16MHz 68000. The Portable could have had the same type of slot as an SE, but SE cards are really power hogs, and they're also rather huge. Neither of those qualities are good for a portable-type, battery-driven computer. NuBus is completely out of the picture for the Portable, so what else is left for the Portable to use, if the engineers want a slot? No one complains when Toshiba comes out with a different slot format for their PC-compatible portables, at least I don't think they do. The Portable is a different enough machine, and it will sell enough units that it justifies a different slot format. > -- Scott Storkel --- Alex UUCP: {att,backbones}!ucbvax!franny!c8s-an INTERNET: c8s-an%franny.berkeley.edu@ucbvax.berkeley.edu FIDONET: Alex.Lau@bmug.fidonet.org (1:161/444)
esf00@uts.amdahl.com (Elliott S. Frank) (10/06/89)
In article <STORKEL.89Oct4144438@rudist.shell.com> storkel@rudist.shell.com (S. Storkel) writes: > >Maybe I'm being short-sighted here, but it seems incredibly stupid >for Apple to have four totally incompatible interface slots. Only >IBM would do something this stupid. It would seem to me that the >smart thing to do would be to make ONE type of interface slot that >would be the same across the entire Macintosh family. What happened? Take a look at the _Guide to Desiging Cards and Letters for the ..._. On the SE, the SEx, and now the Portable, they created an interface that provides aftermarket access to the internal processor bus. This keeps aftermarket products from having to either modify or clip onto the Apple Mother board. :-) And all of the internal processor busses are different... Unlike the classic Macs, problems in the Apple part of a processor- direct-slot-Mac with an aftermarket product in it can be fixed by the average (and some of them are *very* average :-)) dealer. (I.e., if it doesn't fail with your video/accelerator/etc. board removed, then it's not a problem with the Mac. If it does fail with the board removed, then the service tech can do a board swap on the Apple board and send the removed part back to Apple for refurb....) Yes, you only get one slot. But if you wanted a Mac with slots, you would have gotten a Mac II[cx][ix]....... -- Elliott Frank ...!{hplabs,ames,sun}!amdahl!esf00 (408) 746-6384 or ....!{bnrmtv,drivax,hoptoad}!amdahl!esf00 [the above opinions are strictly mine, if anyone's.] [the above signature may or may not be repeated, depending upon some inscrutable property of the mailer-of-the-week.]
pcmeier@phoenix.Princeton.EDU (Pascal Constantin Meier) (10/09/89)
In article <18009@pasteur.Berkeley.EDU> c8s-an@franny.Berkeley.EDU.UUCP (Alex Lau) writes: >In article <STORKEL.89Oct4144438@rudist.shell.com> storkel@rudist.shell.com (S. Storkel) writes: >>Maybe I'm being short-sighted here, but it seems incredibly stupid ..... >>interfaces (best bet: SE/30 and Mac Portable sharing the same type >>of interface). Sure it would have been a little bit more complicated, > >NuBus is completely out of the picture for the Portable, so what I was wondering if it would make sense for someone to build a connector which would use the Portable's slot to connect to an External NuBus configuration. That way, one could use the Mac Portable as a data collector, but when you were at a desk, you could use it to run with other cards. Is this feasible (ie. what's the transfer speed, does the NuBus need 68030 to perform resonalbly, anything else I might have overlooked ??) Just wondering, Pascal