iMac

The iMac has been shrouded in mystery since its announcement by Apple — and some of the puzzles just won't go away, even now the first machines have shipped. Martin Russ investigates.

On the basis of Apple's advance publicity many commentators bemoaned two things about the iMac: that the built‑in modem would be a 33.6Kbaud model, and that the machine would have no expansion slots. When the first production iMacs arrived, therefore, it was a pleasant surprise to find that Apple had uprated the modem to 56Kbaud. Like the prototypes, however, the released iMac still did not appear to have a PCI slot, and Apple made no mention of such a thing. So when I got the email from an iMac owner telling me that the iMac did have a PCI slot, and that Apple had just not told anyone, then I experienced that sinking feeling of being wrong‑footed on home territory. I tried to find out for myself — and the answer to the question: 'Is there a PCI slot in the iMac?' seems to be neither yes nor no, but something much less tangible.

In the old days, before the Internet, whenever something new was released, it would take some time for it to be absorbed into popular culture. Nowadays, within a few hours (or minutes!) of something happening, the Internet is full of detailed comment and analysis. Within hours of the first iMac being sold, the Internet had details abut pulling it apart, and putting it back together — complete with the intermediate stuff too. Speed‑bumping it (at your own risk, as always) to 300MHz and beyond was discussed, and an astonishingly capable Japanese person managed to rebuild the missing part of the PCB that contained an Apple Desktop bus socket! The accessible and almost inaccessible RAM sockets, and the video RAM sockets, were examined in depth. But nowhere was there any mention of a PCI socket.

Well, not quite nowhere, because Apple's own web pages contained their own downloadable detailed description of the iMac specifications and technical information, and this is full of mentions of PCI. Except that the PCI buss is used merely to connect together the processor module with the main logic board. The PCI buss has become almost ubiquitous in just about every computer now, and so the support chips mean that it is a logical choice for just connecting peripheral chips together on a local on‑board buss — as in the iMac. So the 'Grackle' memory controller/PCI buss bridge and 'Paddington' I/O controller/buss arbiter chips found in an iMac need not be there because there's a PCI lurking buried, they are probably there because they are low‑cost, familiar devices to the Apple designers. The Apple document makes no mention of any extra expansion connector, although there are reports of an expansion slot which although not PCI, might well be some variant of it — after all, the logic goes, since PCI is used to connect the G3 PowerPC processor to the rest of the iMac, surely any expansion slot would be PCI too...

The official line from Apple at the time of writing was that the iMac has USB peripheral sockets, two SO‑DIMM RAM sockets and one SO‑DIMM video RAM socket. Unofficially, the Internet has details of a way of getting an Apple Desktop bus connector, a curious technique for hooking in an external monitor (using the internal connector!), rather dubious hacking of standard floppies to suit iMac, the revelation that the CD‑ROM drive ought to be removable, since it is the same one found in PowerBooks, and an increasing number of rumours about PCI...

So, it looks like the closed box that was the iMac on release has opened up slightly. The challenge of 'It doesn't have...' and 'You can't...' seem to have brought out a lot of highly skilled and knowledgable people out of the woodwork to see if they can. The good news is that this is not the reaction of a market to an obscure, one‑off novelty — these people can all smell money, and going by the reception that the iMac has had so far, they are probably right.

Imac And Music

Check out Vision DSP at www.opcode.com

Before I stop writing about iMac, I really ought to summarise the position with music, MIDI and audio as it stands at the time of writing (although it is moving rapidly even as I type!).

• USB depends critically on drivers. Whatever you buy needs a special driver, otherwise nothing much happens. At the moment, some devices only have drivers for Windows 98, but these should quickly be supplemented by iMac/MacOS drivers.
• USB can also provide some power, which means that USB MIDI and audio devices need not suffer from tiny mains power supplies and flimsy power leads.
• You may well read about something called 'audio‑over‑USB (AOU)'. This isn't quite what it sounds like — it means that it is possible to use USB to carry digitised audio signals, but the intention is that this is used to connect speakers to a PC using USB, instead of stereo 3.5 mm jacks. There may be future misuses of this in the music world, but the initial launches of USB 'digital speakers' and 'USB digital audio' are not as significant as they might sound on the iMac. The replacement of the iMac's internal speakers with personal stereo extension speakers will be via jacks for the time being — AOU support is coming soon!

• Opcode's DATport provides a very different (and more useful in hi‑tech music terms) type of audio interface — between S/PDIF and USB, which means that DAT and CD players with digital I/O may be hooked into an iMac. Gold‑plated S/PDIF connectors and support for 48 and 44.1kHz sample rates at 16‑ or 24‑bit depths complete the picture. This is different to the AOU facility, and the whole question of supporting these additional types of data on the iMac's USB is still being resolved — which means that the hardware is USB‑compatible, but that some changes are needed in the iMac software from Apple to enable audio to be transferred. I spoke to some Opcode people recently, and USB is very firmly on their agenda (I also held a real DATport: £169 including VAT from SCV); they are also working to put iMac USB MIDI support into OMS.
• Roland's SMPU64 64‑channel/4‑port MIDI‑to‑USB interface with bundled patchbay software apparently works on Windows 98 computers now, and Apple are working on making it and other forthcoming USB MIDI interfaces work on the iMac. Prices were at rumour/unconfirmed status when I wrote this. SOS reader Gary Hardman spotted one of these whilst in Japan recently (thanks for the info Gary!) and the street price there was apparently something less than £100!

www.rolandcorp.com/japan/product...‑MPU64.html

www.edirol.com/mpu64.html

www.edirol.com/ua100order.html

• Roland have also announced an 'Audio Canvas' (the approx $400 UA100) which provides USB access to GM/GS type outputs using analogue and S/PDIF, and also MIDI I/O...
• Copy protection is an unfortunate fact of life for many Mac music applications, and this often takes the form of floppy key disks, Apple Desktop bus (ADB) or Serial port (printer or modem) dongles. Third‑party floppy drives with USB connectivity are appearing, and video adaptor innovators Griffin Technology have announced a USB‑to‑single ADB adaptor, the $39 iMate, which looks strangely dongle‑like! To be fair, many of the software protection schemes often have options which do not rely on hardware. If I talk to a manufacturer who insists on copy‑protection, I always lobby them for a non‑hardware method. Perhaps if we all mentioned this the next time we buy an upgrade...

www.nashville.net/~griffin/imate...

• Back to adaptors: The Keyspan USB Serial Adaptor is a USB‑to‑twin‑serial‑port adaptor, whilst there is the Keyspan USB PCI card for owners of existing Macs (or PCs) who want to add USB ports. There have also been reports that a Griffin iPort adaptor has been successfuly used to connect a MOTU MIDI Timepiece AV, so things are moving on the 'adapt your existing serial‑port connected' MIDI interface front too.

www.keyspan.com/

• On the PCI question, I'm afraid that only time will tell. By the time you read this, the iMac will only have been out for just over two months, and it may take time for the full story about its expandability to come out into the open. It seems that if there is a port then it may only be PCI‑like, and this takes us into a realm of special iMac‑only cards, which never really took off on previous 'proprietary expansion port' Macs... USB access should provide both MIDI and audio facilities, and so PCI may not turn out to be as important as it might currently appear.
• SCSI support for all those AV hard disks is an obvious no‑no. USB and Ethernet aren't particularly well suited to the demands of digital audio storage, but there is a light on the horizon: Firewire, the faster, 'pro' version of USB. Apple have apparently hinted that Firewire support may be available as an add‑on to iMac, which could mean access to external storage at suitable speeds. The Firewire access might well be through the 'PCI‑like' socket that may or may not ever provide a PCI port...
• Okay, so you're a non‑iMac user who has read so far and is about to say grumpily: 'So what?' The answer is that the iMac is probably a very big set of clues as to where things may be going with future Apple Macs. We may not see SCSI vanish overnight, but the ADB and printer/modem serial ports must surely be in imminent danger, and the kick‑start from iMac may well see USB and 100baseT as tomorrow's givens. Six‑slot PCI might also be harder to justify if USB or Firewire does take off... And I'd be very surprised if the next Macs are beige after Apple's current advertising campaign!