Yellow Pig's BBC Computer Pages

The BBC Master 512

GEM Version 3

The version of GEM supplied with the BBC Master 512 is version 2.0. You can install and run Version 3 on the Master 512, and the resources for doing so are available from this website, but there are a few things to note if you are to get it to work properly, particularly if you use 5¼" floppy disks to transfer files between the PC and the 512 (assuming that you normally download files from the Internet to a PC). Also you will be very limited if you do not have a hard disk drive for the BBC.

Remember that, unless a program needs GEM 3, you may well be better off with the Master 512's supplied version because the effective screen is bigger (256 lines instead of 200). Also I know of no colour version of GEM 3 that will run on the 512. (See my description of GEM Configuration for instructions about using the colour version of the supplied GEM 2.)

The package downloadable from here is actually Version 3.11. It includes the GEM System plus several applications. These are: First Word Plus (a word processor), GEM Paint, GEM Draw, GEM Graph, GEM Publisher and the Programmers' Toolkit. There is no documentation supplied for any of these, so you will have to find that elsewhere or work out how to use the programs for yourself. Many features are self-explanatory anyway.

Installing and Running GEM 3 on the Master 512

GEM was originally distributed on a collection of floppy disks. To create the package here, the contents of each of the disks have been zipped into an archive (one for each disk) and the resulting collection of zip files has again been zipped together into a single larger archive. This avoids having a large number of small files to download and manipulate.

To install, it is suggested that you follow the procedure outlined here:

Download the GEM 3 package from this site to the PC. Unzip the main archive into its constituent smaller archives. Each of these represents the contents of one of the original floppy disks. Three floppy disks contain the GEM System, and the applications mentioned above are on the others. The archive names should make it clear which is which. (Note that in one particular situation one of these archives may be too large to handle conveniently, so there are also a couple of half-disk archives included.)

GEM can only be used effectively with a mouse, so make sure an appropriate mouse driver is installed on the Master 512. The supplied version of GEM 2 includes a mouse driver for the Acorn mouse as part of the screen driver. This cannot be used with GEM 3, and no PC mouse driver will work either. A mouse driver for the 512 is available (also from this site) so download and install it if you haven't already done so. It makes sense to include it in your AUTOEXEC.BAT file. Make sure the mouse is plugged into the BBC Computer's User Port, of course.

Begin with the three GEM System disks, and expand the zipped archives onto the actual disks you are going to use for the installation. (These are the files gem311_1.zip, gem311_2.zip and gem311_3.zip.)

There is a minor complication here that can make this process slightly fiddly in some situations. The issue arises because all of the files that originally came on each of these three disks must remain on a single disk. If you are using 5¼" disks to transfer files between the PC and the 512, then these must be formatted as 360kb, because that is the only format that both machines can recognise. However, each of the sets of files that needs to go on each of the installation disks takes up more than 360kb. This means that for installation the files have to be copied onto larger-capacity disks, so that the files that need to remain together on each disk can do so.

So prepare three larger-capacity disks. They might as well be in Acorn 800kb format since this is the largest and fastest format the Master 512 can use.

You can simply unpack everything on the PC then, keeping a careful track of what belongs where, copy batches of files onto 360kb disks, and then use the Master 512 to copy each of them to the correct 800kb ones. This is tedious, though, and easy to mess up.

An alternative is to copy the zipped disk archives themselves onto 360kb disks, and unzip them onto the larger disks using the 512 itself. Version 2.04g of PKZIP will run on the Master 512, provided you use PCCE, or you may have a different version that doesn't require it.

Note that in the case of gem311_3.zip, even the compressed archive will not fit on a 360kb disk. To help with this I have split the files for Disk 3 into two sets in the archives which I have called gem311_p.zip and gem311_q.zip and provided them along with the gem311_3.zip. If you wish to use these, unzip the files in one to an 800kb disk, then add the files in the other to the same disk.

The above is only an issue for those using 5¼" disks to transfer files between the two machines. If you use 3½" disks then then they can be (and indeed must be) formatted as 720kb. (See here, for example, for how you may use such disks on the BBC.) In this case each of the file-sets will fit on a single disk and the disks can be used directly to install from. Also, if you use a serial cable to connect your PC and 512 and transfer files across that, then the process is also pretty simple, just sending the files from the PC and putting them on (say) 800kb floppy disks on the 512.

Important: Before starting the installation you must put the correct volume label on the three GEM system disks after you have unzipped to them. (GEM Setup recognizes the disks by this.) If you are unzipping them on a PC with PKUNZIP, then use the option -$ to cause the volume label to be written. However this will not work on the Master 512. (If you try, the volume label is written as a normal file, but all other files on the disk are deleted!)

To write the volume labels on the 512 use the LABEL utility. You cannot just enter the label at the command line because there are spaces involved. But if you simply enter:

LABEL

then you will be prompted for the label, and at this prompt you can enter spaces. The disks must be labelled as follows:

	Disk 1:		GEM SYSTEM
	Disk 2:		GEM SCREEN
	Disk 3:		GEM PRINTER

Note that there are two spaces between the words "GEM" and "SYSTEM" on Disk 1, and equally two spaces between "GEM" and "SCREEN" on Disk 2. Note also that the labels must be entered as capital letters.

At this point start the installation. Insert the first disk into Drive A: and enter A:GEMSETUP and follow through the instructions. The Setup program will only install from Drive A:.

The Setup program will ask for some basic information. It should, of course, be informed that the screen is a CGA screen running in mono. It may not make much difference, but it seems most reliable to tell it that the mouse is a "Bus mouse".

A pointer to the GEMAPPS directory should be included in the PATH. This might be included in the GEM.BAT file. (Without it GEM will not know where the applications are, and will not be able to associate applications with file-types properly.)

The installation disks for the GEM applications can be expanded from the zipped archives in a similar way to the system disks. The volume label does not matter for any of these, but it is important to retain the directory structure, so if you are using PKUNZIP, then remember to include the "-d" option. Some of the applications include an INSTALL utility. All this does in each case is to copy the files from Drive A: to Drive C:.

Other Points to Note

Installing on a Floppy Disk

If you do not have a hard disk for your BBC Computer, then it is still possible to install GEM 3 on a floppy. You will be limited in what you can do with it, but if you only want to run one or two of the applications this may not matter to you.

To do this you will need to trick the Setup program so that it "thinks" your second floppy is a hard disk.

One way of doing this is to use the DISCID program which comes as a part of the Ramdisc Utilities package, and which enables you to re-assign drive letters. With this program available enter:

DISCID B: C:

to rename the second floppy disk C:. The Setup program will then think it is a hard disk and happily install GEM to it. (It is perhaps a good idea to do this before you run GEM each time too, otherwise you may keep getting reminders that the hard disk is not responding.)

If you are going to do this, then it makes sense to use the largest-capacity floppy disk that you can, so I would only be inclined to use 800kb floppies. You will not be able to get all the applications together with the GEM system on one floppy disk but you can get several on, especially if you dispense with the sample files.

How Many Hard Disks are there?

GEMSETUP thinks the Master 512 has three hard disks. It gets this value from the "LASTDRIVE" value that DOS-Plus gives it, which by default is E:. You can change this value if you find it annoying, but you must do it before running GEMSETUP. (Once the installation is complete then the number of hard disks cannot be changed.) An explanation of how to do this is in the FIDDLOAD documentation, which is part of this collection.

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