[comp.sys.amiga.misc] How PC compatable is a PC-XT Bridgeboard ?

igreenaw@hemel.bull.co.uk (ian greenaway) (05/07/91)

I currently own an Amiga 500 with extra bits and pieces, and an old IBM PC-XT
type clone.  As i would like to expand my Amiga system, it seems a good idea
to sell both the PC and A500 and get an A2000 with PC bridgeboard.

I am not worried about speed (I know the XT Bridgeboard is slow) as the PC
isn't used very often anyway.  What I need to know is how compatable it is to
the real thing. 

I would also be interested in knowing the specification of the Bridgeboard, if
anyone out there has it, and also info about what s/w comes with it (if any).

I also understand that by using a PC hard drive controller and MFM type drive,
that you can set up partitions for the amiga and pc.  If you had two hard 
drives, could you have one for amiga and the other for the pc ?   Can you 
copy files from the amiga to the pc ?  How about from the Bridgeboard's 5 1/4"
drive to the amiga's 3 1/2" drive and vice versa - can it be done easily ?

Can the amiga access the 5 1/4" drive ?  Can the pc use the amiga's mouse ?
How about the serial & parallel ports ?


So many questions - sorry.

Thanx in advance to any replies.

Cheers

Ian Greenaway  alias igreenaw@hemel.bull.co.uk

(The man with no .sig !!)

drysdale@cbmvax.commodore.com (Scott Drysdale) (05/08/91)

In article <1991May7.145054.2740@hemel.bull.co.uk> igreenaw@hemel.bull.co.uk (ian greenaway) writes:
>I currently own an Amiga 500 with extra bits and pieces, and an old IBM PC-XT
>type clone.  As i would like to expand my Amiga system, it seems a good idea
>to sell both the PC and A500 and get an A2000 with PC bridgeboard.
>
>I am not worried about speed (I know the XT Bridgeboard is slow) as the PC
>isn't used very often anyway.  What I need to know is how compatable it is to
>the real thing. 
>
>I would also be interested in knowing the specification of the Bridgeboard, if
>anyone out there has it, and also info about what s/w comes with it (if any).
>
>I also understand that by using a PC hard drive controller and MFM type drive,
>that you can set up partitions for the amiga and pc.  If you had two hard 
>drives, could you have one for amiga and the other for the pc ?   Can you 
>copy files from the amiga to the pc ?  How about from the Bridgeboard's 5 1/4"
>drive to the amiga's 3 1/2" drive and vice versa - can it be done easily ?
>
>Can the amiga access the 5 1/4" drive ?  Can the pc use the amiga's mouse ?
>How about the serial & parallel ports ?
>

the xt bridgeboard (A2088) contains:
	- 4.77mhz 8088
	- 512k of ram
	- CGA emulation on the amiga screen
	- MDA emulation on the amiga screen
	- pc keyboard emulation
	- mouse drivers for using the amiga mouse (note: no hardware-level
	  mouse compatibility - you have to use the supplied driver)
	- parallel port emulation through the amiga's parallel port
	- ability for the pc to boot from a "partition" (actually a large
	  file) on an amiga hard drive
	- ability for the amiga to access a partition on a pc hard drive
	  (the amiga cannot boot from the pc hard drive, as the amiga must
	  start the pc up.  you'd need a small boot floppy to kick things
	  off)
	- utilities for ms-dos which allow reading and writing files from/to
	  amiga disks
	- low density floppy interface, able to handle two floppy drives
	  (360K 5.25" or 720K 3.5").  one or both floppies can be attached
	  to an internal drive connector, or you can have one internal
	  drive and one external (A1010 or compatible 3.5", or the A1020
	  (at least i think that's the external amiga 5.25" drive)).

i'm not sure what floppy drive is shipping (if any) with 2088's.  i think
you get a 5.25" 360K which is intended to be mounted internally to a 2000,
but i've also heard that the marketing guys are unbundling the floppy from
the package.  check with your dealer on this point.

as to compatibility, there are no major problems.  the parallel port emulation
cannot be used for protection dongles - it's not real-time enough for that.
the only loss is the ability to use a COM2: serial port, since IRQ3 is used
by the janus software and there's broken COM2: emulation hardware on the
bridgeboard.

in a 2000, you can have either three XT slots and three amiga slots, or
two XT slots and four amiga slots, depending on which of the two bridge
slots you install the 2088 in.

>Ian Greenaway  alias igreenaw@hemel.bull.co.uk

  --Scotty
-- 
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Scott Drysdale           Software Engineer
Commodore Amiga Inc.     UUCP {allegra|burdvax|rutgers|ihnp4}!cbmvax!drysdale
		         PHONE - yes.
"Have you hugged your hog today?"
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=

peterk@cbmger.UUCP (Peter Kittel GERMANY) (05/08/91)

In article <1991May7.145054.2740@hemel.bull.co.uk> igreenaw@hemel.bull.co.uk (ian greenaway) writes:
>
>I would also be interested in knowing the specification of the Bridgeboard, if
>anyone out there has it, and also info about what s/w comes with it (if any).

           A2088          A2286
clock:     XT 4.77 MHz,   AT 8 MHz
RAM:          512 KB         1 MB
Software included is MS-DOS 4.01 (I believe) plus some "Janus utilities",
see below. They include software for emulating a PC harddrive on a normal
Amiga drive (harddisk or even floppy!).

>I also understand that by using a PC hard drive controller and MFM type drive,
>that you can set up partitions for the amiga and pc.  If you had two hard 
>drives, could you have one for amiga and the other for the pc ?   

YES. I do.

>Can you 
>copy files from the amiga to the pc ?

Yes, there are utility programs provided for each direction, AREAD, AWRITE.

>  How about from the Bridgeboard's 5 1/4"
>drive to the amiga's 3 1/2" drive and vice versa - can it be done easily ?

Do you still mean PC format <--> Amiga format? If yes, then see above.
With a little effort you could change the PC side drive to a 3 1/2"
drive (on AT BB just a jumper).

>Can the amiga access the 5 1/4" drive ?

Not directly. You see, MS-DOS is not reentrant, so if you access PC
hardware from the Amiga side and you don't know what's running there
just in this moment, you could crash it. Thus the above mentioned
transfer utilities only work from the PC side where they have control
of the situation and may interrupt the multitasking Amiga side whenever
they want without risk.

>  Can the pc use the amiga's mouse ?

Yes, I even think we have the original Microsoft mouse driver.

>How about the serial & parallel ports ?

Parallel: If a software uses the regular DOS interrupts to access it,
        then it can easily be switched to the Amiga-side port via a little
        Amiga-side utility. If the software directly bangs on the parallel
        port hardware, then it should fail.
Serial: No provision to emulate this.
You may well put in an I/O card on the PC side. The only issue to
consider is that you must not use I/O addresses and interrupts for
COM2, these are used by the system for PC-Amiga communication.

-- 
Best regards, Dr. Peter Kittel  // E-Mail to  \\  Only my personal opinions... 
Commodore Frankfurt, Germany  \X/ {uunet|pyramid|rutgers}!cbmvax!cbmger!peterk

dltaylor@cns.SanDiego.NCR.COM (Dan Taylor) (05/09/91)

In <1991May7.145054.2740@hemel.bull.co.uk> igreenaw@hemel.bull.co.uk (ian greenaway) writes:


>I would also be interested in knowing the specification of the Bridgeboard, if
>anyone out there has it, and also info about what s/w comes with it (if any).

Quick summary:  the A2088 is a 512k CGA/MDA XT clone.  I have yet to find
a program that runs on an XT of those specs, that won't run on my bb.  The
included software is MS-DOS, 3.3, or later, and GW-BASIC on the XT side,
and a library on the Amiga side.  The XT side has utilities for copying
files between the processors, each to it's own filesystem.  The bb can
access both the parallel port and the mouse, through Amiga server programs.
The standard configuration does not allow either processor to directly
access a floppy attached to the other, just pass files back and forth.

An XT-compatible hard drive controller is plug-and-play.  Virtual filesystems
can be supported by either processor, for the other (or both at once).  I
use a completely formatted autoboot XT disk, which is a file on one of my
Amiga hard drives, as drive "C", and a second virtual XT drive, "F", as a
file in RAM:.  The latter is wonderful for compiler temp files.  I do
not have an XT hard drive, so I cannot comment on how well the bb supports
Amiga filesystems, but the hd virtual drive I use seems faster than ST-506
XT drives.

I bought my A2088 to support a Xeltec EPROM/PAL/Micro programmer, which
uses an XT-bus interface card.  Works beautifully.  I have been cross-
compiling PDC, using my inexpensive PC "C" compiler.  I have found that
keeping the source on the Amiga side, so I can use multiple windows to
edit, search, etc., and a batch files that copy from the Amiga, then
compile, work really well.

There has been some discussion of the necessity to "reseat" the pluggable
chips on the A2088.  I have not had the problem, but enough postings have
been made to suggest it is real.

Since you accept that the 8088 bb will not be faster than a real XT, I
would only suggest a bit of additional RAM, to get to 640k, and serial
ports, probably combined on one expansion board.

Dan Taylor