PC Jr | Everygamegoing

Personal Computer News


Published in Personal Computer News #064

Kenn Garroch swings with IBM's newcomer to the jungle.

Baby Blue

Kenn Garroch swings with IBM's newcomer to the jungle

The PC jr or Peanut is IBM's bid to win a place in the home micro market. Since they have done so well in the business area this, at first sight, seems like a good idea, though at a cost of around £1,200 it will probably be rather too expensive for a home micro.

The PC jr comes in the usual two pieces of the keyboard, with its infra-red connection, and the brainbox containing the processor, memory, disk drive, cartridge slots and so on. This box measures about 18" x 4" x 18" - quite a bit smaller than that used on the IBM PC sr - and is distinguished by the two cartridge slots under the disk drive. Also quite light, it has a cooling fan which is pretty quiet and soon becomes unnoticeable, even in a quiet room.

On switching on, the colour monitor comes up with the famous Big Blue logo and a test pattern across the screen showing all the colours available. The review machine had 128K of RAM and, as the machine did its memory check, this could be seen ticking away at the bottom of the screen.

Most of the boot-up options are similar to those for the IBM PC but some are a little different. If no disk or cartridges are inserted, the system boots up into the onboard ROM Basic. As with the larger PC, this system has the nasty habit of trying to access the disk before deciding there is nothing in the drive and running Basic. The version of the language in the ROM is cut down compared to the version available from the cartridge and appears to be identical to the one on PC sr, probably due to them both having the same ROMs.

If, before booting up the machine, a PCDOS system disk is inserted into the machine, the junior boots up into PCDOS 2.10. This allows the machine to run virtually all the software available that will run in 128K for this operating system. It will run Wordstar but, unfortunately, won't run the IBM Microsoft Flight Simulator, though it may well be possible for Microsoft to remedy this. The PCDOS operates in exactly the same way as on the large PC, with access to all the standard commands and features.


There are two main storage media available on the PC jr: cassette and disk. The disk is actually an upgrade and the smaller machines run purely on cassettes and cartridges. The single disk drive gives 180K of storage which, according to the DSKCHK routine, is actually 179712 bytes. When running Basic programs this is quite adequate. But if the system is to be used under PCDOS it could turn out to be pretty limiting. When all the system files have been put onto the disk only 23552 bytes are available for use. Using Wordstar, that's around 3,000 words if they're short ones.

The disk access times appear to be similar to the PC sr. When it is grinding away, the system ignores typing ahead but, strangely enough, gives out little beeps indicating that the keyboard is being monitored but the characters are not being stored in a buffer.

The amount of RAM available for use is 114688 bytes and will vary a little with the type of screen display usd, leaving as little as 81920 bytes for programs - quite a lot for a home machine.

One unusual feature is the availability of cartridge software. Two cartridges came with the review machine - a game called Mine Shaft and the Basic, IBM/Microsoft version J1.00. The game is not terribly exciting and the screen display consists of block graphics and defined character shapes. If they are anything to go by, cartridge software will have to increase in quality and quantity if it is to sell at all well.

When a cartridge is inserted, the machine reboots itself and goes through all the hassle of accessing the disk drive, to see if a disk is present. If there isn't, it will eventually boot the cartridge. The left socket is tried first, but the machine is not fooled by placing a cartridge in the right socket and boots that one if there is no left cartridge.


The display is capable of producing 16 colours and a maximum of 640 x 200 pixel high resolution graphics, depending on the screen mode being used. In the highest resolution mode, the graphics are 640 by 200 dots but the range of colours is reduced to four.

Mode Descr Width Mem. Size Colours
0 Alpha 40, 80 2K, 4K 16
1 320 x 200 40 16K 4
2 640 x 200 80 16K 2
3 160 x 200 20 16K 16
4 320 x 200 40 16K 4
5 320 x 200 40 32K 16
6 640 x 200 80 32K 4
Table 1: Screen Display Modes

The colours come in two palettes giving options between green and cyan, red and magenta, and brown and white plus all the usual blues and greys.

To begin, the display is in 40 columns. When used with PCDOS it is not really very much use. A utility is supplied, from PCDOS, which changes this to an 80-column display, allowing the directory and the business software to run properly. If used with a TV set, this 80-column mode will probably be virtually unreadable, but with a monitor it gives a fine solid display. From Basic there are seven screen modes available giving the different resolutions, colours, and so on.

The character set includes upper and lower case letters, numbers, continental characters, and a set of predefined block graphics. The last may be of some use when writing games and can be obtained directly from the keyboard by using the control key as a shift, Commodore style, though they are not printed on the keyboard.

The high-resolution graphics are quite good but the commands to use with them are a bit feeble. They are fairly fast, however, and should allow some nice games to be implemented. But as we said above, the game supplied on cartridge does not use any of these facilities and gives the impression that nobody has really tried anything clever yet.


The documentation supplied with the machine comes in two manuals and a book. The manuals are in the usual IBM-sized folder-type packaging. The first is a guide to operations and is obviously aimed at the younger user with wealthy parents. It is written as a guide to getting the machine going and is full of pretty little colour illustrations of children using the compilcated facilities available, like pressing the buttons on the keyboard. This very simplified manual shouldn't pose problems to anyone, that is if they bother to read it.

Sections outline some of the differences between PC jr and PC sr.

In the appendices all the instructions have been included to allow the system to be upgraded with the usual line drawings showing how to take the machine apart and fit disk drives and so on.

The second manual, covering the Basic in detail, is a lot more upmarket and vastly more useful than the other book. Each keyword is documented and graphics and communciations options are covered. It's all in all an excellent manual for the programmer.

The 430-page Basic tutorial volume, Hands On Basic, leads the new user, in a series of sessions, from switching on the machine to the use of arrays. It is well illustrated in full colour and aimed at the novice user. Most users will probably outgrow this book in a couple of weeks and, since it doesn't provide very much reference material, it will soon become redundant.


Interfaces available on the machine range from the infra-red keyboard connector, audio output, joysticks, cassette, composite monitor, IBM monitor (RGB), light pen, serial printer (RS232C), modem connector (110-330 baud), TV and output to the real keyboard connector. Most of these are at the back of the machine and are denoted with letters such as S for serial and C for cassette.

There appears to be no documentation on exactly what these letters mean and though most of them were pretty obvious it is possible some users may be a little confused.

The modem speeds available are only 110 and 300 baud, so connecting to Prestel could be a problem when using the IBM modem. But it should be posible to use the other serial output, which allows the usual range of speeds from 75 baud up to 4800 baud.

The two other standard speeds, 9600 baud and 19600 baud, did not seem to be implemented.


Smaller than average, the keyboad does have the usual 62 keys. Its main feature is its infra-red link, which means that the keyboard is not physically attached to the main computer and can be moved around the room while the keys are being pressed. It is possible to operate the keyboard up to 20 feet (6.1 metres) away from the machine.

When the keyboard is so far away that the computer cannot understand the signals that are being transmitted, it objects by giving out a little beep. Aside from the difficulty of typing with one hand, while holding the keyboard with the other, the infra-red link makes the keyboard ideal to use on the knees while reclining in an armchair.

At first sight the keyboard is a little tacky and resembles an oversized Oric. After a while it becomes quite easy to use although touch typists will not like it. An odd feature is the way the letters and functions of the keys are not printed on the keytops but above them, on the backplate. From a normal typing position, with the keyboard level, it is not possible to see what the keys do. The solution to this problem is to use the little clip down legs on the bottom back of the keyboard to enable it to be tilted at a better angle.

All of the keys are colour coded, making the function and Alt key combinations easy to follow. The ten programmable functions are obtained by pressing the green function key and then the appropriate number.

There does appear to be a little problem with the keyboard buffer when using the function keys in Basic. If a long word is defined into a key and then the key is held down, eventually the buffer fills up and the key reverts from producing its function and produces the key number instead. This is not a major problem but it is a hitch which can prove confusing.

There is an optional keyclick that can be turned on or off, but is hardly necessary since the keyboard does have a positive feel and there isn't really any doubt as to whether a key has been pressed or not.


The Basic supplied on cartridge is far superior to the internal ROM version and gives access to a whole host of commands including a set of interrupt traps for the keyboard, a light pen, the joysticks and the on-board timer. In addition to these, there is a White loop, a trace function and full RS232 controls.

As Basics go, this one is a very comprehensive version of the standard Microsoft.

The PCDOS is version 2.10, which is very similar to version 2.0. All the normal commands are available, and although no manual was supplied with the review machine, presumably one comes with the disk upgrade.

In Use

The PC jr can be used in three main roles. The first is as a games machine with the cartridge or cassette software and as this type of machine it performs well. But few people will want to use it for this, considering the price of the overall system.

Its second role - as a programming machine - uses the cartridge Basic and the cassette or disk for storage. Programming is easy and in general uses very standard Microsoft, with the usual editor and associated commands. Additional commands available, such as the error and the interrupt trapping and the joystick input, will make it very easy to write games.

Other facilities such as the RS232 control commands mean that it should be relatively easy to implement quite a sophisticated communications package. The graphics are easy to use from Basic and, using the excellent Basic manual, drawing pictures and general full colour graphics is quite straightforward.

The third role is as a business machine running PCDOS. The disk drive will need to be fitted to access the plethora of software ready to emerge for this system, but as an upgrade most users committed to the machine will find it a good deal. When running under PCDOS the PC junior operates just like an IBM Personal Computer but does have the problem that it is limited to 128K.

The disks are the same format on both machines so swapping software between them is no problem.


Given time to adapt to the idiosyncracies of the keyboard, users will find the PC jr a comfortable little beast with no nasty habits. Its PC sr upwards compatibility may find it a niche in the home computer market, with the fact thatit is made by IBM also having something to do with this possibility.

It is not yet available in Britain, unless it has been specially imported as had the review machine. IBM was vociferous as ever when questioned about the matter and neither confirmed nor denied whether the junior would be released or possibly made in Britain.

A few IBM dealers may have imported it, pointing to the possibility that IBM wants to see how it will be received before committing itself to a major effort.

Considering the price and what comes with it, it may well not compete very well in this country due to the number and quality of home machines already available.


Price: Possibly around £1,200
Processor: 8088
Memory: 64K expandable to 128K
Interfaces: Two joystick inputs, RS232 serial
Cartridges: UHFTV, IBM Monitor, Composite Monitor, two cartridge ports
Keyboard: 62 keys, including 10 function keys
Screen: 20 x 25, 40 x 25, 80 x 25, 640 x 200 high resolution graphics (lower resolution possible with more colours) 16 colours maximum
Operating System: Basic or PC-DOS if upgraded
Preview system supplied by Bonsai Ltd, 112 New Oxford Street, London WC1. Tel: 01-580 0902

Kenn Garroch