IBM's NEXT GENERATION Two of the really nice touches are The IBM PC-AT had claims made for it on its release that the two-speed, temperature-controlled it not only harnessed the most advanced technology cooling fan and the lock. The new T') fan makes this system a lot quieter (hence the :A but also surpassed the original PC in than any other member of the PC both power and speed (not hard...). Since then there's family, and in many office situations been a fair bit of controversy about how good the AT that can be a real blessing. When locked the PC-AT can be switched is, and claims that it's suffering from too many bugs to on but not used. The operating be commercially useful. Lloyd Borrett took a look at one system won't boot, and the cover of the new machines. can't be removed . Once you're up i and running, locking the system makes the keyboard inoperative. On August 14 1984, three years after were the 16-bit bus support chips Yes, I know .these are but little frilly the introduction of the first IBM required. The chips necessary to bits to many of you, but to those Personal Computer, 113M US released build an 8-bit bus system based on who use a computer for extended the Personal Computer AT (for the Intel 8088 were not only available, periods in the typical office environment Advanced Technology). The PC-AT is but a lot cheaper. The real criticism they are quite important. an Intel 80286-based microcomputer here is that IBM should have released that dwarfs the original PC in compu­ an 8086 or 80186-based system The Meat in the AT tational speed and power. twelve to eighteen months ago when Okay, let's get to the meat of it. The But not only did IBM release this the market was ready for it. Its PC-AT comes as two models. The new-generation microcomputer, it also opposition did. base model gets one half-height 1.2M announced three new operating Well, IBM has answered the diskette drive and 256K of memory, systems (PC-DOS 3.0, PC-DOS 3.10 opposition by leaping ahead to an while the up-market one gets an and XENIX), a local area network Intel 80286-based system, the PC-AT. additional full-height 20M fixed disk (PC Network), and a windowing Forget that IBM says you can only drive, serial and parallel ports, and a environment (Topview). In the months have three megabytes of memory, total of 512K of memory. since August there have been more because the 80286 chip can address Disk storage can be further extended announcements: Virtual Device 16M of memory, and AST Research by adding a second 20M fixed disk Interface, Enhanced Graphics Board, has already announced a multi-function drive, or your choice of a second and Professional Graphics Controller board with 256K, expandable to 3M. 1.2M diske~e drive or a half-height are just a few. In fact, running in its native mode the 320/360K diskette drive. (There is That is a lot for the industry to 80286 can support four tasks, each every chance that someone will come think about. To this day the sages of of which can use one gigabyte of up with a way to add a half-height the microcomputer world are still virtual memory; the chip has all the 20M fixed disk drive when two half­ trying to assimilate it all, but let me instructions necessary to perform the height diskette drives are already in­ give you my brief version of what it required memory management. But stalled .) all means. I'll start from scratch with let's come back to earth. This next bit isn't as confusing as the IBM PC-AT. it may first sound : you can use the The Frilly Bits 1.2M diskette drive to read and write IBM Listened The keyboard has been changed! to 1.2M diskettes with the 1.2M This is one very fast, well thought-out Shock, horror! As a two-finger-and­ format, but you can't read these machine. I've had one since early thumbs typist, I actually liked the old diskettes in eXisting 320/360K diskette November and I'm impressed. IBM keyboard. Quite a few people expressed drives. Well, you'd expect that, has listened to many of the criticisms other opinions, and IBM changed it. wouldn't you? But get this. You can levelled at the original PC and done With over two years pecking out use1.2M diskette drives to read and something about them. letters on the old keyboard the new write to 320/360K diskettes with the A lot of people thought the original one takes a little getting used to, but 320/360K format. Now for the catch. PC should have been based on the it is better. So there are now three Once a 1.2M diskette drive has Intel 8086 chip instead of the 8088. keyboard layouts in use within the written on a 320/360K diskette, that Actually I thought it was a wise move IBM's Personal Computer family: on diskette can't be read in a 320/360K at the time; the 8086 wasn't readily the original PC, the 3270/PC, and the diskette drive. available, and more importantly nor PC-AT. As the PC-AT I'm using doesn't yet 20 base memory. To get 640K of base SYSTEM UNIT memory, as in the PC and PC-XT, an additional 16-bit bus 128K memory expansion card must be purchased. SYSTEM BOARD The 512K memory 16-bit bus memory 80286 80287 Oscillator H Power Supply expansion cards available from IBM Microprocessor Co-processor 115/230 go into the extended memory area above the one megabyte limit of an Speaker 16 Interrupt ROM Speaker H Intel 8088. Extended memory will be ' , Connector Levels fully exploited by XENIX when it 7 Channel RAM Keyboard H Keyboard becomes available. PC-DOS 3.x can DMA Controller J only use it as a RAM disk. There are eight full-length expansion CMOS Real-Time Battery H Battery slots in the PC-AT. Six support both Clock Connector the old 8-bit and the new 16-bit bus, two support only the 8-bit bus. Some of the current option boards can only Fixed Diskette be used in the two 8-bit bus slots, Disk Drives while others can't be used at all. The Drives IBM colour graphics adapter board is ~~,"",I ~~~~~~~~ an example of one that must be in the 8-bit bus only slots. Fixed Disk and The new combination parallel and Diskette Adapter serial adaptor uses the same 25-pin 00000 0 connector for the parallel port, but a 9-pin connector for the serial port! If only they were the other way round! Monochrome Display and Monochrome Display I'll rarely use that parallel port, but Printer Adapter ' now I've got to get special communi­ Graphics Printer cations cables made up for the serial Serial/parallel Color Printer port. Adapter The PC-AT uses a CMOS RAM Light Pen and a rechargeable battery to store Color/Graphics , the hardware configuration, instead of Monitor Adapter Color Monitor switches on the motherboard. This saves having to open up the box and Prototype RF Modulator reset switches when different combi­ Adapter nations are being tested. Believe me, there are times when you really wish 128KB Memory you didn't have to keep taking the Expansion cover off and putting it back on. The battery also keeps the built-in calendar 512KB Memory clock going. Exppnsion The Software Game Control Joysticks Now for the really important stuff, the Adapter software. To use the PC-AT, PC-DOS ~ Synchronous Data Link Control Adapter Binary Synchronous Communications Adapter System diagram of the AT. have a 320/360K diskette drive, and I like to move my work around between the various systems based on availability, that often eliminates the PC-AT from contention. Think carefully as to whether you should add a 3201 360K diskette drive if buying a PC­ AT; I would be very hesitant about adding a second 1.2M diskette drive. The 512K of memory available on the motherboard is referred to as 21 TYPE OF PO.,WER BATIERY KEYBOARD DISPLAY SUPPLY REAR PANEL CONNECTOR CONNECTOR SWITCH CONNECTORS ...Jcn weI: Z~ Zu <w uzJ:z 00::::u 80286 RAM JUMPER SPEAKER CONNECTOR The AT's system board. 3.0 is required. It has the changes most is the ability to use the COUN­ aren't really worth the additional necessary to support the new 1.2M TRY = option in the CONFIG.SYS file expenditure. Okay, you would get a diskette drive, the 20M fixed disk to specify Australia. Most of the DOS few nflw features, but it also uses drive, the calendar clock, and so on . commands then display the time and more memory. Wait, and buy DOS There are a few nice additions to date in our format instead of the 3.10 Wl1en you want PC Network DOS 3.0, such as an IBM-supported usual US format. support !ater on. RAMDISK driver, a change volume If you're an existing user of DOS labels command, and an enhanced 2.0 or 2.10, I wouldn't rush out and Incompatibility? print command. The one I like the buy DOS 3.0; the few extra nice bits Currently there is one big problem 24 with the PC-AT: not all the existing PC software will run on it.