Acorn Archimedes Fuelled by Acorns innovative ARM RISC processor, the Archimedes or A series offer workstation power and spectacular graphics abilities at PC prices. With their place in education already assured, Dick Pountain believes their speed may also guarantee them entry into the business world.

98 PCW AUGUST 1987 Ever since Acorn first announced the details of its ARM RISC processor chip it has been quite obvious, despite rather feeble denials from the company, that ARM was intended to power the successor to the venerable BBC Computer. ARMs designers quite openly stated their goal, which was to produce a 32bit replacement for the 6502, all the major competitors having been rejected as inadequate. When last year Acorn launched the Master, a slightly repackaged Beeb, it was received in the press with something approaching scorn, and many people expressed scepticism about whether Acorn had the wherewithall to do anything useful with ARM. With the launch of the Archimedes or A series of computers, we can see that the Master was merely a stopgap measure, and that behind the scenes One concession to industry standards is the Archimedes keyboard, which Aeorn was giving everything it had to offers both IBM PC and BBC Model B compatibility. Like the Model 300 it ARM technology. It has been well worth has red function keys, presumably to persuade BBC Model B owners to upgrade the wait. The A series machines offer to an Archimedes. A threebutton mouse is fitted as standard workstation power at prices, and they deliver this power to the ecute in a single clock cycle. Like the old handle up to eight sound channels in programmer in an easytouse way, 6502 which partly inspired it, it gets its stereo. The sound generation facility resulting in truly spectacular graphics speed from short instructions rather than provided is rather simple compared with abilities. fast clocks (the 4MHz clock yields roughly dedicated synthesiser chips like the It would be as well to clarify the status four MIPS). Indeed, it was designed Ensoniq, but fancy stuff can be done in of this Benchtest. At the time of writing, specifically to be usable with cheap software, exploiting the tremendous the production models A305, A310, A440 dynamie memory parts, unlike many new speed of the ARM. and the A410 were not quite finished. ultrafast processors which require The MEMC chip can address and Instead what Aeorn loaned to me was an astronomically expensive static RAM and refresh up to 4Mbytes of actual RAM, A500 Development System. This 25MHz clock rates to get their but also has the capability of translating machine, which is not on sale to the performance. This has been a major logical to physical addresses so that a public, is what Acorn uses for internal factor in allowing ARM to be the first 32Mbyte logical address space can be development of A series software, and super processor to find its way into a supported. This can be used to provide has been distributed to selected external massmarket micro. a diskbased virtual memory system, or software producers for some months. It Weve heard much less about the three to provide hardware memory protection has a very similar hardware specification peripheral chips which Acorn designed to for multitasking systems; that is, to that of the highend A410 model ( go with the ARM CPU, and which were stopping one task interfering with 20Mbyte hard disk, one floppy, 2Mbytes launched in late 1986. These are the anothers memory. As an aside: its been memory), though it uses the older ( VIDC Video Controller, the MEMC the lack of such hardware protection for 3micron process) versions of the ARM Memory Controller and the IOC the 68000 (Motorolas Memory Manager chips which are very slightly slower than Input/Output Controller. All four chips are having been hugely delayed) that has the 2micron production versions. The used in the A series machine architecture, hindered the development of serious system software I saw was at various forming a complete designer chip set. multitasking software on the Mac, ST stages of development; none was final The VIDC controls a colour display with and . and some sections were incomplete. one, two, four, or eight bits per pixel: that The MEMC doubles as a DMA You should, therefore, read this more is, from monochrome up to 256 colours. It controller which manages the buffers for as a preview than a review, and I shall includes a 16word colour lookup palette video, sound and cursor data. It is also point out various places where the which allows a choice from a total of 4096 the glue which sticks all the four chips production machines will differ from the colours, and has onchip digitaltoanalogue together, providing as it does the A500. You may also be confident that any converters to directly provide RGB processor clock signal and all other bias will be in the right direction; the signals. It also supports a hardware system timing signals. production machines will be better than cursor in up to three colours, and directly The IOC controls system interrupts that which I tested. controls VDU timing parameters in a and the system bus. It contains a programmable way. Its pixel rate is number of timers, a serial keyboard Hardware programmable between 824MHz (the rate interface and logic for talking to other Enough has been written about the Acorn at which the machine supplies information peripherals. ARM chip (in this magazine, by myself, to the screen). Its hard to translate that The importance of this allAcorn chip for one) that I shall only briefly describe directly into maximum screen resolution set is twofold. The careful packing of this new proeessor. It is a full 32bit because there are some tricks which functions into the four chips removes the processor of classic RISC (Reduced allow it to look like 96MHz in certain need for a lot of socalled glue logic and Instruction Set) design. It uses 27 32bit circumstances; briefly, it can support a so keeps the overall chip count low. But registers and a small instruction set of 44 1024x1024 highresolution mono display, also the chips are optimised to work simple instructions, almost all of which ex 640x256 in 256 colours or 640x512 in 16 together, using pipelining and other colours. tricks to maximise the performance of Rather surprisingly the VIDC also the whole combination. There is no provides the Sound Controller. It can compromise due to mismatch with other peoples chips, and this shows in the performance. Practically all that is

AUGUST 1987 PCW 99 BENCHTEST needed to make a computer out of the 2Mbytes rather than 4Mbytes of RAM. there are rather more of them. I have four chips is to add some disk controllers The keyboard, however, was quite never been a regular Beeb user so I was and some RAM and put it all in a box. different from the production model, lost in Arthur at first; the fact that it The actual specifications of the cased in metal with only 10 function keys, shares some command names with Archimedes machines are as follows. and covered in keys with names like PCDOS (for example, DIR) which do There are two series of machines, both of HELP, MENU, LOOKS and AGAIN which different things didnt help. which live under the generic name certainly dont do what they say (some However, I soon learned to get around Archimedes. The A300 series are the dont do anything at all). Arthur and found that it has some direct replacements for the BBC Micro The hard disk in the A500 is most attractive aspects. For example, it has and Master and will bear the BBC logo. noticeable for its ferociously rapid access the Unixlike facility to define aliases for The A400 series is more upmarket, speed. It loads huge programs with a faint commands whose names you dont like. featuring internal hard disks, more burping noise, in the time it takes to blink In fact, it is very strong on configuration memory and more expansion capabilities, an eye. The reason for this speed is that altogether; stored in the CMOS RAM and will be sold under the Acorn logo ( the disk is run with no interleaving of there is a list of 30 system parameters, and maybe later Olivetti?). sectors. On an IBM XT, for example, the such as the amount of Font space and The lowest cost machine, the £799 disk rotates about six times between each number of open files, whose values can A305, comes with 512k of RAM, while the read to give the puny CPU time to digest; be inspected using STATUS and altered A310 has 1Mbyte; the A305 is Archimedes eliminates this dead time as using CONFIGURE from the keyboard. It upgradable to 1Mbyte by simply the ARM processor can suck stuff off the is also possible to assign strings to the populating vacant RAM sockets. Both disk as fast as it can rotate. function keys interactively from the models have one 3½in floppy drive, The A300 models can be expanded with keyboard using KEY, and control whose disks can be formatted to 800k or a second drive, or with a characters may be embedded in such to 640k for Master compatibility. 20Mbyte Winchester if the backplane is strings. Any text file of commands can be All models come in the same system purchased. The podules which fit into the run as a batch file using EXEC, and such unit case, which has a metal top and slots are double Eurocards. So far Acorn files can be created without using an sides and a plastic front panel with an has announced its intention to produce editor by the BUILD command which ergonomically inclined (that is, at hand the following podules: Floating Point, a directs keystrokes into a file. angle rather than flat) floppy socket. The hardware floating point coprocessor; I found Arthurs way with files rather system unit contains a fairly quiet cooling ROM, a card to hold ROMbased disconcerting at first. Filenames have no fan, and the power supply. It has a applications, similar to the BBC sideways extensions to indicate their type, and file smallish footprint about the same as an ROMs; BBC I/0, which reproduees the types are treated in a very uniform Amiga, but large enough to stand the ports of the BBC B and Master, including manner. In fact, only datestamped text monitor on, and the metal box supports DtoA and 1MHz bus; MIDI, the music files, plain text files and binary files are this very robust optional backplane to synthesiser control; and 80186, which distinguished. All files contain a load hold podules. Serial (RS423) and runs an MSDOS environment for IBM address, and if you type the name of any parallel ports are standard but software. kind of file Arthur will do its damndest to requires a podule. The A400 models load it. Arthur knows about Basic source come with 14Mbytes of RAM and four Software programs and executes them correctly expansion slots for podules are fitted as without you having to load Basic standard, as also is the Econet socket. The operating system for the Archimedes explicitly. Acorn tells me that in the All the models include a massive 512k series is new, and is called Arthur (after finished product Arthur will know more of ROM containing the operating system the King rather than Daley, one hopes). about more file types in this way, and be and Basic. They also share a Like the BBC operating system before, it able to pick the correct application to batterybacked clock/calendar and 256 is modular, the disk filing system being open a given file, as the Mac does. bytes of nonvolatile CMOS RAM for kept separate from the machine operating The other intriguing aspect of Arthur is system configuration. Video output is system or MOS. This means that that it can load files to any address in analogue RGB or composite alternative disk filing systems can be memory; its memory allocation strategy monochrome. Acorn supplies a colour loaded, and indeed two alternatives are is utterly different from CP/M or MSDOS monitor capable of 640x256 resolution, supplied. The ADFS (Advanced Disk style systems. This makes it very easy to but for the very maximum resolution you Filing System) is a descendant of the have several coresident programs, and will need a NEC Multisync or equivalent. ADFS on the Master. It supports a for data files to load themselves without All models share a keyboard design, hierarchical directory structure and all the the use of an application program. For which is virtually a clone of the 101key usual utilities for creating, deleting and example, a picture can be displayed IBM Enhanced Keyboard, with just one housekeeping disk files. The other filing simply by typing the name of the picture special BBC key named COPY. This is a system supplied is ANFS (Advanced data file, which loads itself into video very smart move; if youre going to copy Network Filing System) which is for use RAM. IBM, copy its keyboards not its graphics. with Econet, and allows access to files At the command level Arthur could not A touching concession to Beeb fans is kept on a remote file server. Changing be described as a friendly operating that on the A300 models the 12 function filing systems is just a matter of typing system, though it has the all the features keys are red! A three button mechanical ADFS or ANFS at the prompt. that programmers need. I found it rather mouse is fitted as standard, which plugs The command line interface of Arthur is spartan, even compared to PCDOS. into an socket on the keyboard. very much like that of the BBC operating On the proper Archimedes machines, The A500 which I used for this preview system, so that Beeb users will be however, Arthur will be hidden from the is closest to the A400; it has a 20Mbytes immediately at home. It uses the same user by a window/ icon/mouse Desktop internal hard disk but asterisk prompt, and also has the FX interface; this , was only in a prototype commands though form on my

100 PCW AUGUST 1987 machine but, nevertheless, looked very good indeed. The overlapping, resizable windows are in colour, and resemble a hybrid of GEM, Windows and the . Each window has horizontal and vertical scroll bars, a zoom box to expand it to full screen, and a close box marked with an X. Acorn uses the mouse in the same way that the original Xerox research team did; the left button is for Select, the middle button is for Menu, and the right button is for Alter. When you press the middle button a popup menu appears at the cursor position (that is, where your eyes are focused), not at the top of the screen. You then select from it with the left button. The idea of pulldown menus along the top of the screen is not employed, possibly to avoid trouble from Apples legal bully boys. Instead there is a thick The back of the Archimedes is relatively sparse by todays standards, bar at the foot of the screen which consisting of: headphone sockets, mono video out, analogue RGB, serial, contains large icons, similar to those in parallel and Econet. The two removable plates above the ports will MSWindows. Five desk accessories, a accommodate podules —that is, peripheral modules clock, calculator, diary/calendar, notepad and colour palette are permanently installed, and directory listings are obtained by opening the disk icons. Windows are resized by grabbing the lower righthand corner using the Select button, while the Alter button allows the window to be dragged across the screen. The power of the ARM is such that the windows respond more quickly than on any other machine Ive tried, with no hint of lag — even more impressive when you realise that this WIMP desktop is written in BBC Basic. The desktop will be automatically entered when the production machine is booted, whereas my A500 booted into the Arthur command line. Arthur also supports the graphics and sound of the A series. This is in contrast to machines like the IBM PC where graphics are performed outside the operating system, by direct hardware Critics of the Model Bs PCB will be pleasantly surprised by the minimal access. Screen modes and colours can chip count of the Archimedes. The absence of glue chips means that it be changed direct from the prompt by has fewer chips than all the popular 16bit and 32bit micros sending Ctrl characters; its even possible structure; WHILE ... ENDWHILE loops to plot points in this way. good enough to create almost are added; a CASE statement has been There are no less than 20 graphics photographic realism. Modes 18 to 20 added; and functions and procedures modes in all, using from a minimum of gives 512 lines of vertical resolution and can now be built into libraries which are 20k to a maximum of 160k of memory. need a Multisync monitor to display held in RAM and invoked by name in The colours available are 2, 4, 16 or 256. them. The teletext mode 7 of the BBC programs. Line numbers are optional, so The highest mode usable on the standard Micro is retained for compatibility. There Pascal type programs can be written colour monitor is mode 15 — that is, are also text modes ranging from 40 using the powerful windowing fullscreen 640x256 in 256 colours. However, in this characters x 25 lines to 132x32 in up to editor which is built in. The obnoxious case the colours are not all independently 16 colours. BBC line editor is still there for those selectable; the palette permits 64 base who are hooked on it. As on the Beeb, colours to be selected, and each one can BBC Basic V The Basic built into Archimedes is any operating system command can be be displayed in four tints (with varying issued from inside Basic by prefacing it amounts of white added). version 5 of BBC Basic, which incorporates many extensions. Some of with a . The 64 base colours can be chosen Basic V is not limited to 64k but can from the total of 4096 only in groups of 16 these are improvements to the control structures of the language, while others address the whole 4Mbytes memory at a time. Nevertheless, the colour range space, allowing substantial programs to available in mode 15 is implement sound and graphics support for Archimedes. be written. Operations on whole arrays While BBC Basic was a big improvement have been added to the language, so over unstructured such as that, for instance, all the elements can s, it still had plenty of warts. be assigned to, added to, multiplied or Almost all have now been removed. In divided by a constant in a single particular, IF ... THEN :.. ELSE ... ENDIF statement: can now span many lines to allow proper DIM A(1000) A() = A() 8 block

AUGUST 1987 PCW 101 BENCHTEST

The Acorn WIMP interface is fast, The usual collection of desk accessories is The Archimedes bundled lander game, colourful and easy to use. The included on the Welcome disk, and written in BBC Basic, is destined to become Archimedes makes this all possible from includes a clock, notepad and calendar as famous as the Amigas bouncing ball a BBC Basic program demo

Arithmetic operations can be rectangle of screen is moved or copied to returns the current mouse position in X performed between two arrays of the another location, in effect a high level and Y and the button status, and you call same dimensions, and matrix bitblit. For example: it as often as needed. The command multiplication is supported between RECTANGLE FILL 10,10,40,40 TO MOUSE RECTANGLE defines the vectors and 2D matrices. 100,200 screen area in which the mouse pointer The graphics and sound extensions would move a 40x40 square of pixels can be moved. I was able to write a quite would take a lot more space to describe from coordinates 10,10 to 100,200 and nifty mouse driven painting program in a in full than is available here, but Ill fill the original space with background couple of hours and 77 lines of Basic. sketch the most important bits. The colour. The most noticeable omission is The Arthur operating system can colour control primitive is GCOL which a general filled polygon routine, though reserve memory space for storing sets both background and foreground you can flood fill any outline using PLOT. sprites; graphic images which can be colours. It can also take an optional The most important thing to note about manipulated as single objects. These are second parameter which sets the logical all these graphics primitives is that they purely software sprites, not hardware plotting mode. There are eight such are blindingly fast. Circle and rectangle generated like those on the Amiga or modes, namely Overwrite, OR, AND, filling is virtually instantaneous. In Commodore 64. Such is the raw power XOR (or FOR as Acorn insists on calling addition to the graphics primitives, there of the ARM, though, that you would it) with the current screen colour, and are FX and VDU commands which can never notice. The supplied sprite editor various logical combinations with the do things like defining scrolling and permits mouse assisted drawing of inverse of the screen colour. These can graphics windows, and printing text in sprites in any of the screen modes (that be used to get special effects such as graphics displays. Then there is SYS, is, in up to 256 colours) and of any size transparency. which• allows direct calls to operating not exceeding the memory allocated, so Drawing is controlled by a number of system routines to be made from Basic. full screen sprites are possible. powerful primitives. MOVE, LINE and Its also possible to write to and read Once drawn a sprite is saved in RAM POINT cater for basic drawing, but the from memory directly using the under a name, and it can be put on the more interesting routines are PLOT, indirection operators, ?,!$ far more screen using PLOT and its name, an RECTANGLE, CIRCLE and ELLIPSE. elegantly than with the cursed PEEK and operation which is fast enough to PLOT m,X,Y is an extraordinary POKE. And if none of this is fast enough, perform effective animation. The stored command, where the first parameter m in the last resort you can CALL machine sprites can be saved to disk and loaded sets one of 255 different modes; these code routines. By combining all these using the operating system commands cover drawing just about anything you features it is possible to write SSAVE and SLOAD; many application can name, including lines, triangles, professional standard graphics programs programs will be started by a batch file rectangles, circles, ellipses, arcs, in interpreted Basic. To my astonishment whieh begins with a list of SLOADs. segments, filled or empty, solid or dotted. I discovered that the Desktop The Basic is extraordinarily fast for an In fact, RECTANGLE, CIRCLE and demonstrations and the font and sprite interpreter, and in applications whose ELLIPSE are just special cases of PLOT editors on my A500 were all written in execution time is dominated by which are easier to use and to read. Basic. arithmetic or graphics operations there is ELLIPSE draws ellipses of any Basic supports the mouse in a very little point in using anything else. The orientation, not just those parallel to the straightforward way through the Basic does show its weakness on axes. RECTANGLE has a special command MOUSE X,Y,BUTTON. This programs which are dominated by loop extension TO, in which a specified timing, however; its performance on Eratosthenes Sieve, at 8.7 seconds per iteration, is pretty average. For this kind of program a compiled language would better exploit the ARM power. Only the most demanding of applications (for example, realtime simulations) would tempt one to use machine code. Acorn has a reasonable amount of developers software for the ARM. There are compilers for C and For

102 PCW AUGUST 1987 BENCHTEST tran, Lisp and Prolog systems, and of Benchmarks Arthur this autoscaling will be provided course an assembler and debugger. Intmath 0.37secs as an operating system service, and the There is a very powerful programmers Realmath 0:41secs fancy fonts will become usable. editor called Twin (because it can use Trig log 2.31 secs twin windows) which was on the hard Textscrn 6.67secs Benchmarks Grafscrn (MODE 1) 6.78secs disk of my A500; it is extremely fast and Times for Store and Retrieve are not includes Econet electronic mail so that given in the timings because a bug in the programmers on a net can exchange For a full explanation of the PCW Benchmarks, version of ADFS supplied stopped them source code and jokes. For see the December 1986 issue, page 164. All running correctly. Results obtained by mathematicians there is an programs are in BBC Basic V Acorn suggest that Store takes between implementation of the Reduce 4 symbolic 23 seconds on the hard disk, and around maths system, and on a 4Mbyte A440 20 on the floppy, but we will have to wait this becomes a very serious proposition, Prices for a production machine to confirm this. in terms of both speed and workspace. A305 I also feel obliged to point out that 512k RAM, 1x640k 31/2in £799 Grafscrn, based on point plotting, is an Welcome disk floppy drive, keyboard, inadequate indicator of Archimedes The Welcome disk supplied free with the mouse, operating system graphic performanee; a test based on line drawing and area filling would show A models will contain the Desktop A310 off its exceptional speed better. program, some tutorials and a number of As above but with 1Mbyte RAM £875 demonstration programs which illustrate A410 the power of the ARM. It will also contain Documentation 1Mbyte RAM, four sockets £1399 65EMU, a software 6502 emulator that I was supplied with photocopies of the for podules, coprocessor bus, one 31 in allows many old BBC programs to run on 66page Welcome Guide and the 640k floppy drive, hard disk controller the A series. I was not able to try this 456page Users Guide, the latter being a emulator, but am led to understand that it A440 Basic manual with enough discussion of will run well behaved software that does 4Mbyte RAM, one 31/2in £2299 the operating system for an enduser. not directly control the BBC chips, which 640k floppy drive, one Both were well written and the Basic will exclude a number of popular games. 20Mbyte hard disk manual is quite complete enough to start Of the demos, the one which is serious programming. destined for instant fame is the game by Mono monitor £50 However, professional programmers D Braben, which on my disk was will need more reference than these cryptically called just GAME1. Its not Colour monitor £200 books provide (for example, ARM much to describe. A flying saucer shaped (All prices exclude VAT) machine code is not covered, nor are the like a wedge of cheddar is controlled by Window Manager calls) and I understand the mouse and flies over a landscape by defining oblique pen nibs. In a similar that a Reference Manual will be available shooting things up. Its the way it does it way, a menu of serifs can be defined to as an extra. that is astonishing. The game is a full 3D be stuck onto characters. Any font can flight simulation, with a stunning be italicised by adjusting a sloping line in Conclusion perspective landseape. You can fly in a window to the desired angle in The A500 felt like the fastest computer I any compass direction, and the rolling degrees. The skeleton drawing part of have ever used, by a considerable landscape covered with trees and the editor uses techniques cribbed from margin. Benchmarks are inadequate to houses unfolds below (its actually a CAD/ CAM to draw curves and lines in convey the feeling of power that exudes cubic surface coloured in a rubber band fashion with the mouse. in use; just about everything you do chequerboard of different shades of With some practice it is possible to happens instantly, and it takes a hefty green). The saucer obeys the laws of achieve professional standard typeface sized Mandelbrot computation before gravity exactly, as does each spark from designs. Fonts are presumably stored as you believe that anything can tax it. its jet exhaust, each bullet from the gun geometric descriptions, rather than Power is nothing if it cannot be and each drop of spray when it flies low bitmaps, and so could be reproduced at harnessed, and the A series allow you to over water. Nothing could better illustrate any size. translate this power easily into results on the screen; they can be programmed the way a quantitative jump in processing Currently, the program is only a immediately by anyone competent in power can lead to a qualitative step in demonstration, as the fonts it creates Basic, without requiring a sixmonth applications. You just cant do this stuff cannot be used on Archimedes. The course of study. on an 8088, and its doubtful on a 68000; resolution of a standard VDU is the hefty calculations of landscape hopelessly inadequate to depict fonts of The A series deserve to sueceed in perspective and particle motion for each this quality, except when blown up to the edueation market in the way the BBC scene need to be performed in less than headline size, and a laser printer or B did before. It will be no surprise if, the screen refresh period or the illusion typesetter would be needed to reproduce unlike the BBC, they make it into the collapses. them. Arthur does have the facility to business field, too, as they have the sort Another impressive demo is the Font replace the system font with a soft font, of power that is becoming essential for Designer, which appears to be inspired but at present this is limited to an 8x8 Desktop Publishing and CAD/CAM by Donald Knuths Metafont. Instead of grid. applieations, at a fraetion of the cost of a defining characters as simple bitmaps on Another one of the demo programs Mac II or IBM PS/2 80. This combination a grid as is usual, it allows you to draw offers a hint of things to come though; it of speed and graphic resolution could character skeletons using lines and displays automatically scaled text (the open up a whole new level of eapability curves, and then to flesh out these font size enlarges and shrinks as the in popular software. skeletons with user defined pens; cursive window is resized) in a variety of fonts, effects (like copperplate) are obtained with antialiasing in three shades of grey to soften the jagged edges. It seems clear that in some future version of is on (02231 245200: END 104 PCW AUGUST 1987