cg@ami-cg.UUCP (Chris Gray) (02/13/90)
I'm one of those software people who "knows just enough about hardware to
be dangerous". With that in mind, here's my view of an Amiga 4000. (I would
say it is far too late for this to influence the Amiga 3000 in any way.)
Note that I have no inside contact with CBM, so anything I say has no
weight other than me thinking its a good idea.
The A4000 case looks a lot like the A2000 case. If anything its bigger. It
has room for a single 3-1/2" floppy drive and a single 5-1/4" half-height
device on the front panel and room for one or two hard drives internally.
Other removeable media must be mounted externally. On the right hand side
are 4 mouse/joystick connectors and a keyboard connecter. Small switches
between the pairs of ports switch the logic signals between the connectors
- power is always applied. (I can finally connect at least 4 of mouse,
joystick, digitizer, 3-D glasses and trackball!) A single parallel port and
a single serial port appear on the back. A small logo on the front looks a
bit lost - there is space under it for lots of little stickers.
Internally, the box has a mother board with not much on it, and a bunch of
slots. Each slot appears to have two connectors - one at the front and one
at the back. In reality, only one connector in each slot is normally used.
There are two independent busses, one intended for main CPU use, and the
other for custom use such as graphics and sound processors. Both busses are
32 bits wide and support 32 address lines (the front one is active if the
high bit is 0, the back one if the high bit is 1). Interbus transfers are
done by the motherboard, and may be a bit slower than on-bus transfers.
Cutouts on the back are available for boards with connectors. Boards such
as memory boards can be plugged into either bus - just turn the board
around. Physical space says that all boards on a given bus are at one end
or the other.
The basic box would probably sell for (all prices US dollars) $1300.
Available boards (part numbers are for discussion purposes only). (Which
bus to plug them into is a suggestion only - the user can choose.)
A4001 - contains a regular Amiga 500 on a card. Includes all of the current
custom chips, with 1 Meg of chip RAM. An additional Meg of fast RAM is
a possibility. Perhaps a floppy connector on the back. The back
includes a 23 pin video connector, a phono connector for NTSC video
(colour, if its not too hard, please), and a pair of stereo sound
connectors. This board would sell for $300 (CBM might even take a small
loss on it). I'm not sure whether you want the standard serial and
parallel connectors to be included or not. Perhaps this has to plug
into a special slot which lets it take over the motherboard ones. Thus,
for about $2100 you could buy a minimal A4000 system with monitor.
A4640 - contains a 25MHz (33MHz if Motorola comes out with them fast
enough) 68040 and 4 Meg of fast RAM. RAM expandible on-board to 16Meg
using 4 Megabit chips. Price: $2000 (varies with RAM prices)
A4640A - available when Motorola makes the chip available - same as the
A4640, but the CPU is 50MHz. Off-board references are slowed to the
system speed of 25MHz (or 33?). Perhaps a bunch of off-chip cache to
make it really zoom? This board is EXPENSIVE.
A4090 - SCSI/ESDI (sync and async) controller board. Supports 32 bit bus
transfers and has 64K of on-board buffer. Versions are available with
small (<300Meg) hard disks on the card. Price: $500 without drive.
Normally plugs into the front bus - the connector is a bit of problem
otherwise.
A4062 - 32 bit RAM expansion board. Comes with 16, 32 or 64 Meg of RAM.
Can use 4 Megabit or 64 Megabit chips (have they got a pinout yet?)
Price: depends on RAM prices at the time of purchase.
A40MS - multi-port board. Contains 7 serial ports, on-board CPU, etc. $500
A40FB - frame buffer. Has 2 Meg of on-board RAM, along with a fast colour
lookup table. Display is 1K x 1K by 8 bits deep. A control register
allows switching between two memory banks for display. Would normally
plug into the rear bus. $1500 (a monitor for this is probably $3000)
A40VP - video coprocessor. Contains a video coprocessor with local buffer
memory and local program memory. Uses a 32 bit off-the-shelf video
coprocessor chip. Rear bus. $1000
A4DSP - digital signal processor. Contains an off-the-shelf 32 bit
digital signal processor chip, along with local buffer memory and
program memory. Includes stereo audio inputs and outputs which DMA
directly to on-board buffer memory. Rear bus. $1000
A40MS - contains an MS-DOS system on a card. Much like the existing ones.
The busses are not any existing standard busses. They are defined by a chip
which CBM produces to interface to the bus. Arbitration of both busses is
performed by two of the chips on the motherboard. The "card" side of those
chips are interconnected to form the bus transfer system.
External vendors are encouraged to produce:
ethernet card, SMD controller card, transputer card, 80860 card, etc.
So, am I totally and completely out to lunch? Why wouldn't this approach
work? (It worked fine for S-100 systems.) I see an argument that a system
built this way is too expensive - discussion?
--
--
Chris Gray usenet: {uunet,alberta}!myrias!ami-cg!cg CIS: 74007,1165baggins@batserver.cs.uq.oz.au (William Segall) (02/16/90)
cg@ami-cg.UUCP (Chris Gray) writes: [92 lines of bliss deleted] >So, am I totally and completely out to lunch? Why wouldn't this approach >work? (It worked fine for S-100 systems.) I see an argument that a system >built this way is too expensive - discussion? >Chris Gray usenet: {uunet,alberta}!myrias!ami-cg!cg CIS: 74007,1165 I want one, tomorrow lunchtime would be fine. Bill.