Archive Magazine CD 1995/Archive Magazine CD 1995.iso/text/specials/risc_pc

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                Risc PC − A World of Opportunities
                ----------------------------------
                         Paul Beverley

In this article, I will give an overview of the Risc PC. David Webb will
go on to give more technical details in his article on page 6. For an
even fuller technical insight into the Risc PC, see the May edition of
Archive magazine (Volume 7, Issue 8 − £2 from Norwich Computer
Services).

The Acorn Risc PC is not just another in the range of Acorn Archimedes
computers − it’s a completely new concept which opens up a whole new
world of opportunities.

        Forget compatibility...

These days the watchword for computer purchasers seems to be
compatibility − but compatibility to what standard? In 1994, they are
saying, “You’ve got to be PC-compatible” but what will they be saying in
two, five or ten years time?

        ...think adaptability!

Some computer manufacturers would like us to think in terms of
‘throw-away’ computers − it improves their sales figures. They want us
to be locked into a certain type of system and then throw it away and
start again when a new ‘standard’ emerges. What end-users want, however,
are adaptable systems that will allow us to use today’s standards AND
tomorrow’s standards.

The number one design criterion used by Acorn Computers has been
ADAPTIBILITY. This will become clear as I list all the main features of
the Risc PC.

        • Graphics for the future

The Risc PC’s desktop can currently be anything up to 1600×1200 pixels
and you can work in up to 16 million colours (in 800×600 mode). In the
future, you will be able to add graphics cards with an even higher
specification. Theoretically, you could have a 2200×1600 screen in 16
million colours!

        • No speed limit

The speed of the Risc PC600 is roughly twice that of Acorn’s former
top-of-the-range computer, the A5000. What is more, as each newer,
faster ARM processor becomes available, you will be able to pull out the
old one and plug in the new one − so there’s no real speed limit.

One important difference from previous Acorn systems is that the Risc PC
can have separate memory for the screen display. This means that the
video system and the processor are not competing for use of the memory
and so, even if you go into the highest mode of graphics, the processing
speed will not decrease as it does with Archimedes computers. (From
Risc PC onwards, Acorn 32-bit computers are no longer being referred to
as “Archimedes”.)

        • Modular case system

As you can see from the various photographs, the Risc PC comes in
‘slices’ which can be mounted horizontally, like a stacking hi-fi
system, or vertically like books on a shelf. Since you could have up to
eight slices, that should provide enough volume into which to expand!

Inside the case, everything is put together on a plug-in basis, so it
takes only a matter of seconds to open the case and upgrade the
computer’s specification. There are virtually no screws in it and most
upgrades can be done without the use of a screwdriver!

        • Plug-in memory

Acorn have gone for industry-standard RAM memory boards, so you can buy
off-the-shelf SIMM memory cards and plug them in yourself − up to a
total of 256Mb! This means that you can benefit from the lower pricing
of memory packages that are produced for the mass markets.

        • Plug-in processors

I’ve already mentioned the fact that you can change the processor by
plugging in a new one, but the Risc PC has what is called a Dual
Processor Open Bus. This means that you can actually have two processors
working side-by-side, sharing memory, peripherals and screen display.
They could both be ARM processors but they could be different − perhaps
an Intel or a Motorola chip. This means that you can get the best of ARM
technology as well as having access to other mass-market standards.

The first such processor will be a 33MHz (or faster) 486SX, at a retail
price of £99 +VAT if bought with the computer (this includes DRDOS 6).
With a PC Card fitted, the Risc PC will then behave just like a 486 PC
with Windows plus a graphics accelerator card offering SVGA video
(800×600 in 16 million colours). In fact, it will probably work faster
than an actual 486PC computer because the RISC processor will be able to
do the screen update.

Again, if you decide that a 33MHz 486SX isn’t fast enough, just pull it
out and plug in a faster one − or even a 100MHz Pentium processor!

        • PC keyboard and mouse

To take advantage of industry-standard components, the Risc PC uses a
PC-type keyboard. This means that you can replace it with any
off-the-shelf keyboard to suit your own taste.

The Risc PC comes with a normal three-button Acorn mouse but you can
also fit a PC-type serial mouse so, again, you can take advantage of the
whole range of commercially available rodents.

        • Backwards compatibility

Just to reassure existing Acorn users, I should point out that the
Risc PC is backwards compatible. The vast majority of software that ran
on Archimedes machines with RISC OS 3.1 will run on RISC OS 3.5 − the
Risc PC’s operating system. (Details of the extra features of RISC OS
3.5 are in Archive magazine.)

In terms of hardware, we expect that the majority of Archimedes
expansion cards will also work on the Risc PC. Also, it has the same
(but faster) serial interface and the same (but faster) parallel
interface so existing hardware that uses them will be transferrable.
Your existing hard drives (both IDE and SCSI) can also be used in the
Risc PC, although only the IDE interface is supplied as standard.
CD-ROMs, both SCSI and those with proprietary interfaces (like Morley’s
Revolution), can be fitted inside the Risc PC, as can removable drives,
both 5¼" and 3½".

        • Improved interfacing

As well as catering for existing Archimedes expansion cards, the Risc PC
provides for much higher specification interface cards. They will be
able to store many times the amount of information and transfer it
directly to and from the main memory at very much higher speeds than
before.

        • Interface compatibility

The Dual Processor Open Bus will make it possible to set up interfaces
to other proprietary interface cards such as those designed for PCI Bus
and SCSI II Bus. This means that we will be able to take advantage of
hardware that is designed and built for the mass markets, and won’t be
limited to Acorn-specific hardware and software.

        • Networking the world

One of the major areas in which computing will be developing in the
future is networking and, needless to say, the Risc PC is ready for that
future too. The DEBI interface is so fast that it could provide
connection to new high-speed networking facilities but, in addition,
there is a dedicated network port ready and waiting for the next
generation of networking systems.

As it stands, it can be used to plug in an inexpensive Ethernet card
(i.e. not using an interface card slot) but in the future, we can look
forward to ATM network interfaces and whatever follows that.

        A future-proof computer

As you can see, the Acorn Risc PC is a computer which has been
future-proofed to an amazing degree. As the technology develops and you
find that one part of your system has become a ‘weak link’ in the chain,
you don’t have to throw your computer away and start again. Because it’s
such a ‘kit-form’ computer, you will simply be able to change that part
for the latest, fastest, biggest version available at the time.

With the huge variety of interfacing facilities and the adaptability of
the whole system, the range of possible applications is staggering.
Acorn Computers have always had a following of technically excellent
companies developing add-ons for their computers, so it won’t be long
before we see some powerful and highly innovative products appearing,
based around the Risc PC. Also, if Acorn continue to develop their
partnerships with large companies like Kodak, who want to use Risc PC as
a base for other products, we could be in for an interesting and
exciting few years.

As the £99 plug-in 486 processor illustrates, Risc PC gives you the best
of all worlds now, but it also opens up a whole world of opportunities
for the future.  A

                A Vision Restored
                -----------------
                  Paul Beverley

In trying to get my mind around Acorn’s new computer system, I have come
to realise that Acorn’s description of the Risc PC as a “major sea
change” is actually an understatement. I have been describing it as a
totally new concept in computing... but is the concept really all that
new?

        Déjà vu

Consider the following quote...

“It is a very complex system but it is extremely versatile and
expandable. Everything possible seems to have been done to ensure that
this is not a ‘dead-end’ machine which you will have to throw away after
a year or two... ...The basic computer is just the starting point for
connecting to all sorts of other systems.”

That, to me, describes the Risc PC perfectly − but actually, it’s a
quote from an article I wrote in Personal Computer World, July 1982,
talking about Acorn’s “new BBC Micro”.

In April 1994, BBC Micros are still being used for quite serious and
useful applications − certainly in schools, colleges and research
establishments. They may not be the latest technology but how many other
1982 computers do you know of that are still doing a serious job of work
in 1994?

        Déjà vu 2

In that same article, I waxed lyrical about a thing called “The Tube”.
It was a means by which you could have two processors working together
in the same machine, sharing peripherals and memory. See what I mean
about déjà vu? To quote from the same article...

“Choosing a Z80 second processor opens up the vast array of CP/M
software currently available... ...and the planned 16032 second
processor opens up the world of UNIX”

In exactly the same way, the Risc PC opens up the world of PC and
Windows software. It allows you to plug in other second processors that
will give you access to other banks of “standard” software.

        Déjà vu 3

The BBC Micro had a system called the “1MHz extension bus” which allowed
you to access Eurocard circuit boards which provided another major means
of extending the capabilities of the BBC Micro.

In the same way, the Risc PC will allow a range of extra circuit boards
to be added. There is one major difference here though. We are not
talking about having a separate box on the end of a piece of ribbon
cable but one single box that grows, slice by slice, as and when you
need to add to the system.

        A new vision − RISC technology

Eleven years ago, Acorn had a new vision − RISC processors. They
realised that the future of computing lay in using RISC processors. This
vision has found expression in the ranges of ever-faster RISC-powered
computers that Acorn have produced over the last seven years. The
importance of RISC has, of course, now been picked up by other computer
manufacturers − like Apple who have just launched their first range of
RISC-based computers.

However, in Acorn’s excitement over this important new technology, they
seemed to have got side-tracked from the vision that fired the BBC Micro
revolution and started to produce ‘closed-box’ computers.

But that was before the Risc PC...

        A vision restored

With the Risc PC, Acorn have returned to their original vision of an
open system that will combine all the advantages of the brilliant ARM
RISC technology with what ‘the rest of the world’ is doing in terms of
technology − the Risc PC really does bring us the best of all worlds.

It’s really encouraging to see that, once again, Acorn Computers Ltd are
trail-blazing in the world of computer technology.  A

                Risc PC − The Products
                ----------------------
                    Paul Beverley

Acorn are selling the Risc PC in three different configurations although
even the lowest cost version is fully upgradable to the highest
specification of which Risc PCs are capable. There will obviously be
many more additions to the system becoming available in due course and
details will be given in Archive magazine. Here are the details of the
products announced so far.

        The computers

There are three basic versions of the Risc PC600, two with a 210Mb hard
drive and one slice of case (so to speak!) and one with two slices and a
420Mb drive. The ram sizes are 2Mb, 5Mb and 9Mb. The information is
summarised below.



                      ACB15   ACB25   ACB45

DRAM fitted (Mb)    2    4    8

VRAM fitted (Mb)    none    1    1

Hard drive (Mb)    210    210    420

Expansion slots    2    2    4

3½" drive bays free    none    none    1

5¼" drive bays free    1    1    2

Price with 14" monitor    £1249    £1399    £1699

                  (inc VAT)    £1468    £1644    £1996



        The monitors

There are two monitor options offered with the Risc PC600. The AKF60 is
a 14" colour monitor with a 0.28mm dot pitch screen which scans
frequencies from 30 to 50kHz. (This means that the old Acorn modes will
be displayed in “letter-box” mode, i.e. about half height.)

The Risc PC supports Display Power Management Signalling (DPMS) with the
AKF60 monitor. This is a way of reducing the power to the monitor when
the computer is not being used. RISC OS already offers screen blanking
to avoid phosphor dot burn out on the monitor, but this is another
cost-saving feature which significantly reduces the power consumed by
computers in intermittent use.

An alternative to the AKF60 is the AKF85 − a 17" colour monitor with a
0.27mm dot pitch screen and scanning frequencies up to 82kHz. This is a
re-badged Phillips monitor which will cope well with screens up to
1280×1024 and you may even be able to push it up to 1600×1200. This
costs an extra £400 +VAT (=£470) on top of the basic prices given
opposite.

But a 17" monitor doesn’t really do justice to the incredible 1600×1200
resolution of which the Risc PC is capable. You need a monitor like the
20" Taxan 1095 Plus LR. This costs £1995 incVAT through Norwich Computer
Services (or £1745 if bought with a Risc PC instead of the AKF60
monitor). Or if money is no object and you really want the best, there’s
the Eizo 780iW with a 21" tube and a 0.26mm dot pitch. These cost £3350
inc VAT through Norwich Computer Services (or £3100 if bought instead of
the AKF60).

        PC card

The PC card makes use of the Risc PC’s Dual Processor Open Bus and gives
you an extremely cheap way to get “the best of both worlds”. For £99
+VAT, if bought at the same time as the computer, you get a 33MHz 486SX
processor plus DRDOS 6 and manuals.

If you buy it as a separate upgrade later, it will cost you £249 +VAT
for the card, DRDOS 6 and Windows.

        Networking options

Initially, there will be two networking cards available: Econet at £49
+VAT and Ethernet at £99 +VAT. These will be network interface cards,
i.e. they will not take up any of the expansion card slots.

        Case expansion

If you want to add a second slice to an ACB15 or ACB25, you need the
ill-named Tower Option. This provides all the metalwork etc that you
need as well as the four-slot expansion card bus. It costs £99 +VAT
(£116).

        Memory upgrades

If you want to add to the main RAM, Norwich Computer Services can supply
SIMMs memory packages for the following VAT-inclusive prices:

    4Mb −     £150

    8Mb −     £300

    16Mb −     £640

    32Mb −     £1350

We have yet to find sensible pricing for 64Mb or 128Mb SIMMs but they
will no doubt become available in due course.

The video RAM is not a standard product like the SIMMs memory packages,
so it has to be bought through Acorn dealers. To add 1Mb of video RAM to
an ACB15 costs £129 +VAT (£152) or to add 2Mb costs £199 +VAT (£234).

If you already have 1Mb of VRAM and want to increase to 2Mb you don’t
need to pay the full as there will be a 1 − 2Mb upgrade price − see the
Archive magazine for details.   A


                The Risc PC − An Open System
                ----------------------------
                      David Webb, NCS.

Unlike most currently available PCs, Acorn’s Risc PC is not a closed-box
system − it is open − very open. Paul has already explained how the case
is an open, kit-form system which expands very easily to accommodate a
growing computer system. I want to take this a bit further and give you
some more technical information about this exciting new computer.

        Dual Processor Open Bus

Technically speaking, the feature which is most significant in making
the Risc PC an open system is what is called the Dual Processor Open
Bus. This revolves around a chip called the IOMD (Input Output
Management Device), which allows you to have two processors working in
parallel sharing the use of memory, video and peripherals.

The second processor could be another ARM chip to give some degree of
parallel processing, perhaps, for a dedicated task such as digital sound
processing (DSP), network management or graphics pre-processing.

This may sound slightly esoteric but, the huge significance of DPOB
becomes clear when you realise that the second processor doesn’t have to
be an ARM chip − it could be a ‘foreign’ CPU − and this, commercially
speaking, is the most significant factor in the success of Risc PC.

        Open to Intel processors

Can you imagine being able to put an Intel processor (386/486/Pentium
etc) inside the computer, working alongside the ARM processor, so that
you could run both sets of software at the same time? Well, that’s
exactly what Risc PC allows you to do!

Acorn are producing a 486 second processor card which will cost just £99
+VAT but it is expected that third parties will market PC cards using
100MHz 486 DX/3 and P24T Pentium processors.

The 486 card is so cheap because all it has on the card is the 486
processor (a 33MHz 486SX), a socket for a 487 floating point chip, a
crystal to set the 486’s clock speed and an ASIC chip (Application
Specific Integrated Circuit) which is Acorn’s special controller to link
the alien processor to the IOMD.

Later versions of the PC card will offer support for Novell networking,
SCO UNIX and other Intel binaries. A 16-bit sound card, currently being
developed, will provide MPC (Multimedia PC) audio and a subset of the
Soundblaster card for PC games.

        Open for other processors

The 486 is the most obvious processor that people will want to use, but
there is no reason why someone shouldn’t produce a Motorola processor.
(Well, perhaps there is, because Apple have never been very happy about
licensing their operating system software to be run on non-Apple
computers!) You could even use a PowerPC chip and run RISC to RISC!

Other possibilities would be to utilise a DSP processor for speech I/O
or image processing, or an application-specific device such as an MPEG
video processor.

        Open for PCI Bus and SCSI II Bus

The Dual Processor Open Bus can also be a way into other bus standards.
The two most obvious are PCI bus and the SCSI II bus and Acorn are
already working towards providing interfaces for these that plug into
the second processor slot. This will then provide high speed access to
those buses and thus enable ‘standard’ processor and other boards to be
used within the Risc PC.

        Open interfacing

As well as using the two processor slots, other CPUs can be added by
putting them on interface cards. This is an established technique,
demonstrated by Aleph One’s well-established 386 and 486 cards and the
DSP sound processor board which is currently being developed for use on
both Archimedes computers and the Risc PC.

If you have interface cards from Archimedes days, you can still use them
with the Risc PC. However, thinking of tomorrow’s standards, Acorn have
markedly increased the specification of the interface card bus − now
called DEBI − DMA Extended Bus Interface. DEBI provides 32-bit DMA on an
8/16MHz clock so you will be able to transfer large banks of data
quickly and directly.

RISC OS 3.5 is capable of handling up to eight cards although only the
first two will be physically capable of giving the full 32-bit DMA. You
can have up to 16Mb of directly addressable memory on each card which
greatly increases the possible applications of these cards.

        Open construction

Acorn have used an extremely versatile modular case design which
provides a physically open machine. There are virtually no screws in it
and it has a kit-form construction.

The whole case is made of a material known as Bayer Bayblend − a mix of
tough ABS and polycarbonate. It is a high impact-resistant plastic
usually used in visors and riot shields! Then, to cut down electrical
emissions, the inside is metal-sprayed.

As the picture opposite indicates, the case comes in slices with the
same shape cross-section so that each piece sits on top of the other. A
flat lid then goes on the top slice and the whole thing is locked
together by four rods, one in each corner, with a single twist-lock
fitting. As you increase the number of slices, you will need a set of
longer rods, but these will be provided as part of any upgrade.

This form of construction means that you don’t even need to use a
screwdriver when changing memory, processors, etc. The only screws are
one each on the mother board and the power supply, to ensure earthing
standards, plus two screws on each of the DEBI interface expansion
cards. Even the floppy and hard drives are held in with spring clips
rather than screws. (Anyone who has worked on an A5000 will be pleased
to know that the metalwork of the Risc PC doesn’t have those infamous
sharp edges!)

If security is a problem and you don’t want to make it too easy for the
wrong people to get inside your computer, there are padlock holes in the
twist-lock pins!

Within each slice, you have one 3½" bay and one 5¼" bay. In the bottom
slice, the 3½" bay is used for the floppy drive so that the spare bay
could be used for CD-ROM or a 5¼" removable or even a 3½" removable in a
suitable cradle (which can be supplied by NCS).

The 210Mb (or 420Mb) IDE hard drive supplied with the computer doesn’t
use up one of the bays. Instead it hides in the space underneath the
bays − the motherboard is so small that there is space for the hard
drive in the same plane.

Each time you add a slice (or slices − costing about £100 each), you
will get a backplane extension which brings an extra two DEBI bus slots
into each slice. You can put together up to eight slices, so in theory,
you could have eight additional 5¼" devices and seven 3½" devices! These
could be CD-ROMs, fixed hard drives, removable drives, tapestreamers,
etc, etc or the space could be used for other expansion devices, perhaps
using PCI bus or SCSI II bus. It’s a case of “Watch this space...”!

You may need to upgrade the power supply, if you will be drawing more
than the maximum rated current, but apart from one screw, it’s just a
plug-out-plug-in job.

The case can be laid flat on your desk, with a monitor of up to 16kg on
top of it, or on its side in tower mode − whichever suits you best.

        Open memory expansion

The RAM memory used in the Risc PC is ‘industry standard’ SIMM memory
which means, first of all, that it is easy to fit and easy to change.
Also, because it is a well-established standard, there are many
different suppliers available. The markets are large and so, as the
demand for larger memory sizes increases, the prices will almost
certainly fall. Archive subscribers can currently buy SIMMs as follows
(inc VAT): 4Mb £150, 8Mb £300, 16Mb £640, 32Mb £1350.

There are two SIMM slots in the Risc PC and whichever model you buy, the
RAM memory occupies only one of them. Fortunately, you can mix sizes so
you can put whatever other size SIMM you want into the other slot. (The
SIMMs don’t have to be matched pairs as they do in Apple’s new
PowerPCs.) Norwich Computer Services will probably be doing a trade-in
price for SIMMs of 4Mb or more. (More details will be given in future
issues of Archive magazine.)

The other good thing is that if you have any video RAM (up to 2Mb is
possible), RISC OS will automatically make use of it as if it were part
of the main DRAM − assuming it is not actually being used for the
screen.

        Video standards

The Risc PC offers a choice of up to 16 million colours and, with 2MB of
VRAM, you can have this choice at SVGA resolution (800×600 pixels). If
you want higher resolution, even with no VRAM fitted, you can go up to
1280×1024 non-interlaced in four levels of greyscale, or in 256 colours
if you fit 2Mb of VRAM.

These resolutions and colour depths are made possible by the VIDC20
video chip. Video modes are fully configurable by the user, and there is
a direct relationship between resolution and colour depth. So, for some
applications, you may choose a higher resolution at the expense of the
number of colours, and for others, more colours and less high
resolution.

The maximum pixel rate guaranteed is 110MHz, although the typical values
are 135MHz, and memory bandwidth into VIDC is at least 38Mb/s with no
VRAM, rising to 76Mb/s with 1Mb and 152Mb/s with 2Mb VRAM fitted.

The table at the bottom of the page summarises the video performance
guaranteed but 1280×1024 is going to be normal and you may even be able
to push up to 1600×1200.

        Open communications

A major strand of the future development of information systems is going
to be related to communications and networking. What does the Risc PC
have to make it adaptable in that area? Well, you can, of course, put
communications links on serial and parallel interfaces, as with the
later Archimedes computers. The next stage is to use network cards on
the DEBI bus but the Risc PC also has a dedicated network port. Acorn
Universal Networking software is provided as part of the operating
system.

        Open hardware and software

The Risc PC’s main motherboard (see opposite) only measures about 190 ×
260mm − somewhat smaller than a sheet of A4 paper! When you examine it,
the first thing that strikes you is how few components there are on it.
But then when you look more closely and see exactly what the
‘components’ are, you realise that more than half the area of the PCB is
actually covered by connectors!

We have mentioned the connectors for DEBI, two processors, video RAM,
two SIMMs and the network interface but then there are power connectors,
links to the speakers and various LEDs, as well as the floppy drive and
IDE hard drive interfaces. All the connectors along the back of the
computer − serial port, parallel port, keyboard, video and network −
are, again, all part of the motherboard.

Even having accounted for all those interfaces, there are still at least
three other sets of connectors on the printed circuit board. Acorn
realise that, as soon as the Acorn third party companies get their hands
on the Risc PC, they will want to add all sorts of technically
innovative bits and pieces to take advantage of its power and
adaptability. So, in line with their new ‘open’ policy, they decided to
make as many signals as possible easily available for the developers.

        Open co-operation

It’s not just the computer that has taken on a new openness − Acorn, as
a company, is working in new and exciting ways. They are developing
partnerships with a number of other companies to use the Acorn Risc PC
as base for other products with mass-market applications.

All we can say at this stage is, “Watch this space... ”  A


                Risc PC − The Opposition?
                -------------------------
                   Matthew Hunter, NCS.

Acorn and Norwich Computer Services have done some work looking at the
opposition to Risc PC and the initial results are summarised in the two
tables on this and the next page. At the launch of Apple’s first
RISC-based computers last month, it looked as if their pricing was going
to be a real threat to the Risc PC. However, when you look more
carefully at what you actually get for the prices quoted, there is
rather less to worry about than we first thought.

For example, the Apple PM6100 with 8Mb of RAM costs under £1400, which
seems to compare very favourably with the ACB25 with 4Mb of RAM at
£1399. But when you look into it, you find that Apple’s price doesn’t
include a keyboard... or a mouse... or even a monitor!

Also, if you are looking for PC compatibility, the equation changes
further. You can add an actual 486 processor to the Risc PC for £99
whereas to add “Soft Windows” to the Power Mac 6100 or 7100 costs £455.
(All these prices are ex-VAT, by the way.)

Why should Apple charge so much for a software emulator, you may ask?
The answer is that it isn’t just software. The upgrade price includes an
8Mb RAM upgrade. Why? Because Soft Windows is recommended to be run in a
machine with 16Mb or more!

Remember that this is a software emulator and that it runs at a fraction
of the speed of a real PC486 chip. I have no doubt that Apple will be
able to speed it up in due course, just as Acorn have done with their PC
Emulator over the last seven years but, at this stage, there is just no
comparison, either in speed or in price.

Also, at the moment, the only applications available are those that were
written for the older Mac processors running under their own Mac
emulator. Our local Apple Centre say that “the Power Macs won’t run all
existing Apple software, but if software runs under System 7.1, it
should be OK.”

        The real opposition

To my mind, the real opposition to Risc PC still comes, not
surprisingly, from the PC world. However, there are a lot of very
positive points to note when you start comparing similarly-priced
systems. If you can encourage people to actually use a Risc PC, and
compare it with a Windows machine, they will probably be convinced − the
difference in feel in staggering and this is mainly due to the speed of
screen re-draw which is an order of magnitude faster than a
comparably-priced PC.

You can then show them that, for £99, they can also have a 486 processor
in the machine and that it will then have SVGA/XVGA graphics as
standard. That would be equivalent to fitting a graphics accelerator
into their PC but the Risc PC would still be faster than the PC!). I
should think that will make them sit up and take notice.

If you want to go up-market a bit and talk about a Pentium machine and a
bigger Mac, the comparison with the Risc PC is still very favourable as
you can see from the table below. Certainly, the equivalent Power Mac
costing almost £1,000 more, with poor PC emulation and inferior
graphics, is really no match for the Risc PC and, again, it’s the PC
that is the real competition.

        The price of a whole package

When you are doing your comparisons, it is well worth pricing the whole
package for the total job you want to do − that means bringing software
into the equation. The Acorn machines move further into the lead
because, although there isn’t the huge range of software, the prices are
all somewhat less for comparable packages.

Then, if you are worried about the limited range of software available,
remember that for the extra £99, you can run the PC packages on the 486
card. If you want to export the products of that PC software, you can
work the programs in a window on your RISC OS desktop!  A


                Risc PC − Processor Upgrade Policy
                ----------------------------------

An extremely exciting piece of late news is that Acorn have declared a
fixed price policy for processor upgrades from ARM600 to ARM700 and
ARM800. So, as the ARM technology advances, you can know in advance how
much it will cost you to upgrade to any particular new processor.

For example, you can buy a Risc PC600 now, knowing that, to upgrade it
to a high performance ARM 800, will cost a maximum of £175 +VAT. (The
prices will be indexed by r.p.i.)

        How much?

The table below shows the fixed upgrade prices but what it basically
means is that you have a ‘ladder’ of possible upgrades. One step up will
cost you £75, two steps £100, three steps £125, etc. So you could go up
the ladder a step at a time or wait for a new chip that will give you a
more significant increase in processing power.

        How fast?

There isn’t space here to go into the detail of processor speed but, as
an example, the 40MHz ARM700 will be almost 50% faster than the 30MHz
ARM610 supplied with the Risc PC600. (The ARM700 has the advantage that
it has a slot to allow you to plug in a floating point accelerator.)

        When?

Yes, we would all like to know that! (Acorn included!) This will depend
on when the manufacturing standards of the silicon chips can be improved
sufficiently and it is always dangerous to predict that. Current best
guesses are that the first commercially available ARM700’s will be
available in the fourth quarter 1994.

(The ARM700’s do exist. We have actually used a Risc PC with a
pre-production ARM700 and have done some speed tests on it. For more
technical details on that and on ARM800 processor speeds, see the May
edition of the Archive magazine.)

        How?

How will the upgrades be done? The basic method is that you unplug your
existing processor and send it back to Vector Marketing with a suitable
cheque. They will send you a new processor back to you by over-night
carrier. (If you cannot afford to be without your computer, contact
Norwich Computer Services as we may be able to arrange to do the
processor upgrade in a more convenient way.  A