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1 - The PC, Macintosh and Acorn platforms

This chapter will briefly cover the three platforms that I have come to use the most during my time at university and will continue to use throughout my working life.

'The question you have to ask yourself is: are we dealing with computer technology, or do we push multimedia into a market more akin to the video industry? In which case, the players needed do not have to be full desktop machines. A common standard for playback will be set and the industry works to that.' (entries 1 and 2, Appendix A)
Paul Dunning, Access Communications

In each of the following descriptions, I will discuss how the platform was first developed, and how each platform copes with file storage, the most fundamental aspect of cross platform compatibility.

Personal Computer (PC)

The PC is a collective term for any machine which happens to run Microsoft Windows or IBM’s OS2 operating systems. It was formerly known as the IBM PC, when the company IBM devised the first personal computer in 1981. Microsoft won the bidding to design its operating system. Microsoft had never designed their own operating system before, so they bought one from another company and adapted it, calling it DOS.

IBM then allowed Microsoft to keep the rights to the operating system, which was a costly mistake, for they renamed it MS-DOS and licensed it to other computer manufacturers. This began the rise to fortune of Microsoft, for no PC could be a PC without MS-DOS. IBM lost the battle, and the IBM PC, became the IBM compatible. (page 13, Bedell)

In all this time, the standard of a PC has changed every six months. There is no such thing as a single standard. There are many of them, with one being a bit more popular than the others, but not enough to dominate completely. Therefore, designers have to be constantly aware of the latest technology and aim for that as the minimum standard. There are hundreds, perhaps thousands of different configurations, with hundreds of different file formats. By chasing the latest wave of new standards, owners of older machines are left behind, with the increasing chance of not being able to run the latest software.

Files can be kept in two ways on a PC. The first, and therefore standard way of naming files is by adding a three character extension to the filename, which can be up to eight characters long (see Figure 1). This is how pre-Windows 95 machines stored files. The extension determines what type of data the file contains. For example, A Microsoft Word document would be saved with a .DOC extension. If I wish to design multimedia for use on older PCs, then I must name files in this way, otherwise they will not work. On the other hand, post Windows 95 PCs do not require such extensions (see Figure 2). In fact, filenames can be longer, and therefore more meaningful to the user. If you are developing specifically for post Windows 95, then you do not have to use extensions. But, for cross platform authoring, the older method must be used, as both MAC OS and RISC OS still rely on these extensions to determine the PC file’s type.

Figure 1 Figure 1

Figure 2 Figure 2

Cross platform file ratings
PC - Mac = very good, if filenames have the file extension
PC - Acorn = very good, if filenames have the file extension

Apple Macintosh

Developed by Apple Computers and first appearing in 1984, the Apple Macintosh became the computer of choice for designers. In 1984, the PC was still controlled by entering keyboard commands, but the Macintosh introduced the Graphics User Interface (GUI). The computer pioneered the use of an onscreen 'desktop' with icons to represent the disk drive and files, drop down menus, windows containing disc contents or word processed files, all under the control of a mouse pointer operated by the user. I discovered, through my experience of using the Macintosh and through articles in the Macintosh press, that, hidden to the Macintosh user, but more apparent to both PC and Acorn users, supposedly single files under the Macintosh operating system MAC OS, are actually stored as two parts. These forks are called a data fork and a resource fork.

The resource fork can contain code, sounds, icons and other Macintosh information which enable the file to work. The data fork meanwhile holds data information that relates to the file or the application software. Any Macintosh file can hold a resource fork only, a data fork only, or both. (page 22, Bennett?). Either fork will hold a four character creator type and file type, which is also used to determine the icon used to represent the file. (page 281, Thompson, page 122, Schorr).

This method of file storage is unique, opposite the Acorn and PC which use single files, so Macintosh files must be exported as PC files, complete with extensions, because its generic format is not supported as standard on Acorns and PCs. Special software must be purchased in order to read such files.

In order to place Mac icons on PC files so that they can be opened up in Macintosh software, a utility called PC Exchange is provided within MAC OS, where you can type in the PC extension, and match it to the software you want it to be loaded into, and then finally, choose, the filetype icon to actually match that file with that software. To actually map icons to Mac files that have 'lost' their icon, a utility called ResEdit is used to rebuild the forks required to give the file an icon (page 121-122, Schorr).

I find Macintosh machines quite pleasurable to use, except when I am trying to open files from other platforms, when headaches such as disc errors, and software crashes are rampant. It is more standardised than the PC platform, so it is easier to upgrade hardware and software.

Cross platform file ratings (when using PC formatted media)
Mac - PC = very good, if filenames are given the extension
Mac - Acorn = very good, if filenames are given the extension

Cross platform file ratings (Macintosh formatted media)
Mac - PC = not good. PC software required to read Mac media
Mac - Acorn = not good. Acorn software required to read Mac media

The Acorn Computer

This account will concentrate on one particular model of Acorn computer, the Risc PC 600. Designed in 1994, it is the youngest of the three platforms (see Figure 3). Running Acorn’s operating system RISC OS, the Risc PC also possesses the ability to run another operating system such as Microsoft Windows, either at the same time on the RISC OS desktop, or one at a time at the click of a button. It is arguably the only computer in the world that has this ability, making cross platform development extremely attractive.

Figure 3 Figure 3

RISC OS differs from Windows and MAC OS by being based in ROM chips, making the system work faster, and free from infection by computer viruses. RISC OS is also modular in design, so any extra programs needed to perform tasks on the desktop are loaded when the computer is switched on, consuming very little memory in the process.

As standard, the Risc PC lacks support for anything other than PC floppy discs. So Macintosh discs and PC removable media like Syquest discs will not work without extra software. Acorn formatted discs are not supported on any other platform, because of its smaller market share, therefore not warranting support. This is surprising, for Acorn and Apple were joint partners in a UK company, Xemplar Education, which supplies computers to educational establishments. Early in 1999, Acorn left Xemplar, leaving the company as a wholly owned Apple subsidiary.

From the first time I received an Acorn machine in 1985, I have long maintained that the design of Acorn machines, in terms of hardware and desktop interface, far outweighs that of Windows or MAC OS. For designers, the Acorn platform is an extremely pleasurable machine to use. The ability to drag and drop files from one program window to another with one move of the mouse is inspired, compared to the PC which uses a global cut and paste facility which is less 'hands on' in comparison. Companies such as the multimedia arm of Anglia Television, and Sherston Software (both will be mentioned in later chapters) use Acorns to put together top selling titles, which are then ported to the Macintosh and PC.

Cross platform file ratings
Acorn - PC = very good, if filenames are given an extension (Acorn standard files are not supported on any other platform)
Acorn - Mac = very good, if filenames are given an extension for PC media, and with the presence of Mac media reading software (Acorn standard files are not supported on any other platform)

This chapter has introduced the three main platforms that I use, and expressed my opinion on each one. As you can tell, the difference in the way files are stored on each platform bring about many difficulties for the designer. The only solution is to learn what can and cannot be done cross each platform, and to be more aware of the limitations long before the project is started, to prevent hitting stumbling blocks at a later critical phase.



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