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4 : GEM Update        


This chapter provides information missing from the User Guide supplied with the Master 512. As the Guide covers GEM Paint, GEM Write and the Desktop Accessories in reasonable detail, they are not covered here other than to provide vital information missing from the Guide. For full tutorials you are referred to the books listed at the end of this chapter.

GEM Setup

There are what seem to be 'random' problems with GEM Setup in that the settings selected are not always saved correctly. This manifests itself when you come to save selections when GEM Setup requests you to swap discs which are obviously not related to the process! Eventually you will be requested to enter DISC 2 where the setup file will be saved.

When GEM is subsequently booted it will either cause an error or hangup the computer. Equally it may well work – it's a suck-it and see situation. There are no plans to release a new version of GEM Setup.

Mouse Drivers

Programs which run from the GEM Desktop will be able to use the mouse supplied with the Master 512, however, those programs that make use of a Microsoft mouse will not be able to use the supplied mouse. This is because a suitable Microsoft driver is not supplied due to hardware and software limitations. The MOUSE.COM file that is supplied with a number of packages will, therefore, not be recognised by DOS Plus.

Memory Size

The version of GEM supplied on the 512 may limit the use of some applications due to memory limitations. When running, DOS Plus takes 154k of space and the GEM Desktop a further 333k – a total of 487k from 512k. Thus packages running under GEM will often have only very limited space for data storage. As an example, when running, GEM Write has less than 25k available for text files and must, therefore, rely heavily on disc access for all but the shortest files. This restriction can be overcome with the installation of a Solidisk PC Plus board.


As standard GEM Write will only allow the use of underline, bold and italic styles within text. Most printers, especially dot-matrix, will allow a wide range of special effects to be used, for example, superscript, subscript etc. ..CMD is a GEM command in GEM Write that allows the special control characters needed to obtain these to be sent to the printer.

..CMD is used as an embedded command. This is typed directly into the text at the start of a line ensuring that it is preceded with the two full-stops which identify it as an embedded command. The ..CMD must then be followed directly by the printer control codes needed to obtain the effect required. The relevant control codes must be extracted from your printer manual and some guidance on doing this is given below.

For example, the control code sequence needed to turn italic print on and off on an Epson FX80 printer is:

Turn on:    ESC 4
Turn off:   ESC 5

Within GEM Write the embedded command codes would be:

  Italic print now on......
  Italic print now off!

The '>' character represents ESCAPE and is obtained by pressing the ESCAPE key at that point. Please note that there are no spaces anywhere within the command line.

Single Line Feeds in GEM Write

One problem that often rears its ugly head is that of double line feeds during printing and getting a form feed between pages. This is caused by GEM Write sending an extra RETURN character at the end of each line or indeed a form feed at the end of each page of text.

The easiest method to overcome this with most printers is to set the 'CR from host' DIP switch to off, so that the printer ignores carriage returns sent from the host computer. The technique for doing this will be outlined in your printer manual.

If, however, the printer does not have such DIP switches, or other packages that are used in the BBC mode require this DIP switch to be on, then you can tell GEM Write not to send carriage returns. This is done as follows, and only needs to be done once as the setting is remembered:

1)     Boot DOS Plus and GEM as normal, then load GEM Write, but do not load a file.
2)   Move the pointer to FILE on the menu bar and move down to TO OUTPUT. Select TO OUTPUT, which will give you a menu box labelled Create OUT file.
3)   Select Start on this menu box. This will give you the output screen with another menu box labelled START OUTPUT.
4)   Select Cancel, which will leave you with the OUTPUT screen.
5)   Move the mouse pointer over OPTIONS on the top menu bar, then move down the menu to Printer and select this. You should now get a large selection box, labelled PRINTER OPTIONS.

Make sure that the options are set up as follows:

           Scale:       Best fit
  Initial Form Feed:   NO
  Final Form Feed:   NO
  Horizontal Justif:   Center
  Vertical Justif:   Center
  Print in background:   NO
7)   Then select OK.
8)   Reselect the OPTIONS menu, but move down to MAKE DEFAULT and select this. Your new options will then be saved.
9)   You can now go back into GEM Write by selecting QUIT from the bottom of the FILE menu.

When you come to print out a letter that you have written or loaded, you should do the following before going to the output stage:


Move the pointer onto PAGE on the top menu bar. Then move down to FORMAT and select this. You will get a selection box titled PAGE FORMAT OUTPUT. Change the settings so that it is set up as follows:

           Document mode:   OFF
  Pagination:   OFF
  Justification:   OFF
  Line Spacing:   1
  Page length:   66 lines
  Text begins on:   6_ ends on: 60
  Left margin:   1_ characters
You may wish to change some of the above, if you do then make sure that Pagination, Document mode and Line spacing are as above.
2)   To use these settings, click on OK. You can now print out your text with single line spacing and no final form feed.

Printer Control

All printers respond to a very basic language which takes the form of numbers. When a printer receives a certain sequence of numbers it will act upon them. The telephone exchange recognises the numbers you dial on the telephone and uses this to select one particular phone in the whole world. Use a different sequence of numbers and a different phone is called. Send a different sequence of numbers to the printer and a different effect is selected, or perhaps a selected effect is cancelled. The numbers that are sent to the printer are called control codes or ESCAPE codes.

When you select a certain printer effect in GEM Write, bold or underline for instance, GEM Write automatically sends the control codes to the printer for you. However, it is worth understanding how to interpret and use these control codes, as it means that you are able to use many other effects that may be supported by your printer using the ..CMD embedded command in your GEM Write document as described earlier.

To select the effect that you want, you must look at your printer manual to extract the necessary codes – not as painful as it seems – and then send them to the printer using the CMD format.

Printer manuals will normally provide control code sequences in one of two ways, ie ESC or CHR$ codes – most printer manuals have both, so concentrate on the row of CHR$ codes. For example, in a typical Epson printer manual the table to select emphasised (bold) text might look like this:

CODE:      ESC E
PURPOSE:   Select emphasised print
FORMAT:   CHR$(27) "E"
REMARKS:   This command causes the printer to print in emphasised (bold) mode.

All the information needed to produce emphasised text is here! The line we are really interested in is the line marked FORMAT:

FORMAT:      CHR$(27) "E"

Indeed all we have to do is place the sequence:


at the appropriate point in the document and then print it!

Up to a Point

When a printer effect has been selected with an output control sequence, the printer will continue to act on it until it is switched off or cancelled by another command. The manual entry to turn emphasised (bold) print off might look like this:

CODE:      ESC F
PURPOSE:   Cancel emphasised print
FORMAT:   CHR$(27) "F"
REMARKS:   This command causes the printer to cancel the emphasised print mode

To cancel emphasised print, the following embedded command must be inserted in the text:


More Effects

Of course bold text is already built into GEM Write but it is one effect that virtually all printers support. To gain other effects you will need to examine your own printer's manual. The majority of dot-matrix printers are Epson compatible – if your printer is sold as such then the list of CMD codes that can be found in Appendix C could well prove to be quite invaluable. If you are not sure if your printer is Epson-compatible or not then simply create a GEM Write document and embed each command into it with some suitable text to follow, print it and see the results for yourself!

Books on GEM

The following books outline the use of GEM and GEM Write and are available direct from Dabs Press:

Using GEM on the Amstrad PC by Kathy Lang.
Published by Glentop.
ISBN 1 85181 065 X

WP Using GEM Write by M O'Reilly.
Published by Glentop.
ISBN 1 85181 067 6

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