Once upon a time, when computers were the sole preserve of academics, hobbyists and the business community, writing 'user-friendly' programs wasn't exactly high on the software designer's list of priorities. Digital Research's CP/M, the eight-bit operating system standard, was notorious for its terse screen messages. Those whose job it is to devise and write software have always had their own special ways of communicating with the beast — just as everyone has a particular 'language' in their own line of work.

But there were other factors which contributed to the spartan approach. 'User-friendliness' generally requires more memory and extra processing power than most present-day home micros can afford to provide, and that's where the new generation of machines comes in. Strangely enough, their advent coincides with the computer makers' realisation that if micros are to increase their market penetration, both among the business community and with the public at large (and that includes musicians), they must be truly user-friendly. The computer must be bent to the will of the user, not vice versa.

The most immediate way that bending can be achieved is by making a computer's output easy to understand. And the point at which that output appears first — the monitor screen — is where a lot of attention has been recently directed. Following on from Apple's window-and-icons screen display environment (introduced on the company's Lisa and Macintosh micros), a number of other firms have come up with similar approaches to making the monitor's message clearer and more easily comprehensible to the computer novice. Digital Research have given us GEM (Graphics Environment Manager), IBM have developed Top View, Microsoft have introduced Windows, and Commodore/Amiga have a version called Intuition. And if you've been following the antics of the good Professor on those TV ads, you'll know that those dreadful Epson people have their own variant as well, called Taxi. We're even seeing the basic concepts of the environment (which now carries the unfortunate abbreviation WIMP), if not the details, appearing in programs for eight-bit micros like the Spectrum and Commodore 64.

Since we previewed Atari's new 16-bit home computer, the 520ST, in E&MM July, the machine has actually made it into the shops in limited quantities, though the system software is still on disk (the ROM version is imminent, apparently) and music software has yet to materialise. We recently had a 520ST in the office for inspection, and overall, we were greatly impressed with its user-friendliness. Everybody in the Music Maker empire (from the Editor of this esteemed organ right down to the cleaner, and down even further to the Publisher) who had a go on the ST took to it very quickly, regardless of previous computer (in)experience. So it seemed about time to look at how the Atari's version of the WIMP environment presents its options.

But first, a look at the computer world's most notorious rodent, the mouse. This is a small, smoothly-shaped lump of plastic which fits nicely into the average grubby human paw, and plugs into one of the joystick ports via a cable some 3ft long. On the upper side of the mouse are two buttons for selecting options, while the underside houses a roller ball whose movements are converted into screen positions for the on-screen arrow pointer.

Accommodating these rodent manoeuvres doesn't pose too many problems, as the amount of space round which the mouse has to be free to move in order for its graphic representation to span the entire screen is a modest 9" x 7" — less than an A4 sheet of paper. Use of the left-hand button seems to be commonest among mouse-employing manufacturers; the one on the right is there for software developers to utilise as they wish, but the left-hand button is intended to have a standardised function. When you've selected (or 'clicked') an icon for attention on-screen, its image is reversed just to confirm your selection. To select an icon and a further action related to that icon, you have to 'double-click' the left-hand button. You can even tailor the required response rate on double-clicking to suit your own requirements.

If you want to remain keyboard-bound, however, there are QWERTY keyboard equivalents of mouse actions which don't involve too much in the way of convoluted button-pushing. But once you've got used to the mouse (and it doesn't take long) you'll probably want to leave the keyboard well alone.

Let's be realistic about what the mouse will and won't allow you to do, though. It's essentially a quick method of selection, and won't prove any substitute for extended alphanumeric keyboard input, even if its potential is still enormous.

You know there's something different about the ST (as opposed to previous-generation home micros) when you're presented with a message like 'Put the Systems disk into your Disk Drive. After you've done that, move the pointer to the OK box (with your mouse) and click the button'. This sort of friendly, down-to-earth talk would have been unheard of in the days of CP/M.

Once the system software has loaded (which takes 35 seconds), you're presented with the GEM Desktop. This is simply three icons — floppy disk drives A and B (the ST system allows two drives to be daisy-chained) and the ubiquitous trash can — and a menu bar with the four default pull-down menu headers. Everything else is actuated from this basic screen.

One of the first surprises is that you can actually move each of the icons to any position on the screen. This is achieved by moving the on-screen pointer to one of the icons, clicking on the icon and then moving the pointer to any position on the screen whilst keeping the left button held down. The icon follows the arrow to its new position, a process which is termed 'dragging' (well, there's nothing like down-to-earth terminology to break the ice).

Menus are accessed simply by moving the pointer over the relevant header, whereupon the menu automatically drops down. As you move the pointer down the list of options, each one is highlighted in turn. Not all options are available at all times (for instance, you can't list a directory if the disk drive hasn't been installed first), so accessible options are printed in bold and non-accessible options in light. You select an option by clicking on the mouse, after which, in most instances, an icon springs up in response.

The ST allows up to four windows to be open on the screen at the same time, though only one can be active at a time (this contrasts with the multitasking capability of the Amiga, see above). But there are still a variety of ways in which you can manipulate a window and its contents. These can be summarised as moving, sizing, scrolling and closing, and all are activated by clicking on a relevant symbol around the border of the window. You can move a window to any position on (or even off) the screen by positioning the pointer on the Move Bar across the top of the window and dragging its outline around the screen as you would an icon.

Sizing a window is achieved in one of two ways. The first is by clicking on a small box labelled 'Full' in the top right-hand corner of the window, which expands the window to full screen size. The second, more flexible method is to click on the small Size box in the window's lower right-hand corner. By keeping the left button held down and moving the pointer, you can expand or contract the window in any direction.

Moving and sizing are obviously invaluable for avoiding window clashes and leaving selected bits of background visible. And significantly, sizing doesn't reduce the contents of a window — it effectively creates a window on a window, so you then have to scroll the contents by clicking on the relevant direction arrows around the window border.

In addition to windows, the new Atari also confronts you with Dialog boxes (don't ya just love these American spellings?) and Alert Message boxes.

Dialog boxes are fairly self-explanatory. They spring up whenever the ST wants you to give it information in response to something it's presented to you. The standard method of exit from a Dialog box is to click on either an OK or a Cancel box.

The purpose of an Alert Message is to inform you that an action you're attempting to initiate is not, strictly speaking, allowed. At last, the good old error message is presented in understandable and informative English. Here are two examples. 'The GEM Desktop has no more windows; before you open a disk, close a window that you're not using...' is one and 'You can drag the trash can to another location on the Desktop, but you cannot place it on top of another icon...' is another. And you can't get much clearer than that.

I mentioned the four menu headers earlier. In fact, the only menu that's standardised is Desk, with the options VT52 Emulator (send data via modem), Control Panel (set up key and double-click response, bell on/off, colour palette), Set RS232 Config and Install Printer (define printer type, quality and other features). A further option allows information about the current program to be displayed. Beyond this, each program can be given its own menus tailored to its particular requirements, something that offers tremendous potential to software developers.

Of the other 'default' menus. Files allows you to display a file directory, show information on files, set up a new folder (see later), close a file, close a window, and format a disk. The View menu allows you to display files on disk either as icons or text, and to sort them by name, date, size and file-type. Text Display allows date and time of creation for each file to be displayed as well, while the Options menu allows you to install a disk drive, install an application (ie. define the relationship between programs and datafiles), set preferences (ie. tell the computer whether or not you want warning messages to appear), save the desktop and print the current screen. Each menu option generates an appropriate window or 'dialog' box for further action.

File management using the ST's system is almost ludicrously easy. There are three types of file icons: programs, datafiles and folders. A folder is a means of 'subsuming' several files under a single icon, and has been adopted as a means of simplifying the appearance of a directory when lots of files are saved on a disk together.

Folders are created via the above-mentioned option on the Files menu, and a file is placed in a folder by dragging it into the folder icon; a new copy of the file is created in the process. The contents of a folder can be displayed by double-clicking on the relevant icon, and files of all types can be deleted by dragging them to the trash can (which, as the manual points out, is really more akin to an incinerator — you can't retrieve anything from it once you've lobbed it in). A copy of a file can easily be created by dragging the relevant file icon to a different position in the window, and you can copy a file to another disk by dragging it across to the relevant disk icon.

That's about it for the Atari ST and its GEM graphics implementation. The only question-mark hanging over the system as it stands is that a recent agreement between Apple and Digital Research has caused the latter to revise the GEM Desktop. Apple felt the original GEM screen designs were a little bit too close to their own Macintosh displays, so DR have agreed to modify their system. The new Desktop (Version 2.0) will presumably be incorporated into all STs from January '86, as this is the date the system becomes available to manufacturers like Atari. Version 2.0 is said to run at twice the speed of the present one, but the only direct visual changes will be an increase in size for some icons and the odd alteration in menu terminology.

Whatever the outcome of those changes, my impression of the way the Atari ST presents its options to the user remains the same: all the claims about its extreme ease and speed of use are true. And bearing in mind that all these display facilities can be utilised by software developers in their own programs, and tailored to the particular requirements of each program, it's easy to see that the potential is tremendous.

Now all we can do is wait for the music software that'll put the Atari's graphics system in touch with MIDI musical instruments. I hope the wait isn't a long one.