rbharding@trillium.uwaterloo.ca (Ron Harding) (07/21/90)
My roommate and I have access to free Nestar Arcnet cards for the IBM
PC. We will both be getting Amiga 3000s very soon (my first Amiga, he's
replacing his 1000). We have been considering possible ways to use the
Nestar cards in the Amigas.
We don't consider the Bridgeboard an acceptable option. It's too
expensive, and who wants an 8086-based MS-DOS machine, anyway? If CBM
made a 286- or 386-based board with at least EGA graphics, things might
be different...
What we are thinking of is a bus-adapter board which uses the
Bridgeboard slot to connect the IBM slots to the Zorro bus. The primary
function of this board would be to map the IBM bus's 1Meg memory space
into one of the many unused Megs of the Zorro address range. It would
also have to map the IBM's 64K io space into another Zorro range. Which
ranges of the Zorro space are used could be set by switches, or maybe even
Autoconfig.
We have not resolved some issues yet. Unfortunately, the Amiga Hardware
Reference does not describe either Zorro or the 1000's expansion slot
($%#^#%@%#!!). The issues we are concerned about are:
- The IBM bus provides 6 or so interrupt request lines. We're pretty
sure that it would not be hard to use switches to map the IBM's 6 IRQ
(or at least the ones that are in use) lines to some unused Zorro
interrupt request lines.
- The IBM bus provides 3 DMA channels. Is it possible to map these to
Amiga DMA channels just like the interrupts? DMA is not essential
for most IBM cards anyway, but wouldn't hurt.
- Many cards for the IBM PC are very slow. The Nestar is probably one
of them. In fact, some original PC cards are so slow that they won't
even work in an AT, since the shortsighted designers of them didn't
give the option to generate wait-states. Newer IBM network cards have
a jumper to specify the number of wait-states they need. You set the
jumper if you have a 33 Mhz 386. You don't need it for your 4.77Mhz
PC. It would be quite desirable to have the real old, slow cards
without wait-state jumpers work, since they are cheap. We don't plan
on using any hard-disk controller boards, so blazing performance is not
a concern. It should be acceptable to have the bus-adapter
automatically throw some switch-selectable number of wait-states into
every IBM bus access.
- Any IBM cards we will be concerned with are 8-bit. The 68030 seems to
have special instructions for dealing with 8-bit peripherals ( the
MOVEP instruction, for example). I don't remember offhand whether or
not the IBM slots in the 2000 or 3000 are 16-bit long-slots or not. If
so, then there may be special challenges. I seem to recall that IBM
long-slots allow bus-mastering. Not something I want to deal with...
Just imagine the possibilities if this is do-able! There are quadrillions
of cards for the IBM PC in the world. There are only a handful of Zorro
cards. With this card, you could have internal modem cards, fax modems,
extra video cards (VGA or whatever), any network card (Ethernet, Token-
ring, Arcnet, etc), A/Ds and D/As. All sorts of stuff. You'd have to be a
hacker-extraordinaire to get a lot of it working, but then you are reading
this newsgroup, aren't you?
This is getting a bit long. Has anyone out there considered the
challenges of this? If you've already built such a beast, we'd love to hear
about it. On the other hand, if you know of some reason why it's not
possible, well, who asked ya, anyway?
=============================================================================
Ron Harding | Nuke'Em: Get them before they get you!
rbharding@trillium.uwaterloo.edu | Another quality home game from Butler Bros
=============================================================================greg@walt.cc.utexas.edu (Greg Harp) (07/21/90)
In article <1990Jul20.172301.6908@watdragon.waterloo.edu> rbharding@trillium.uwaterloo.ca (Ron Harding) writes: [Lotsa stuff removed] > We have not resolved some issues yet. Unfortunately, the Amiga Hardware >Reference does not describe either Zorro or the 1000's expansion slot >($%#^#%@%#!!). The issues we are concerned about are: Speaking of which, where is the best source for the Zorro II/III specs and the A500/A1000 expansion port specs. I'd _really_ like to design some expansion hardware for the Amy, but I can't do it by squinting at the schems. in the back of my "Intro" to the Amiga 500 manual.... >============================================================================= >Ron Harding | Nuke'Em: Get them before they get you! >rbharding@trillium.uwaterloo.edu | Another quality home game from Butler Bros >============================================================================= ..greg... ___ Disclaimer: The opinions expressed above are not my own, but AMIGA! //// the property of some higher-up power, to which I am only a tool. //// "Welcome, my son. Welcome to the machine." -- Pink Floyd ___ //// "Reality is only a simulation, and it's still in beta testing." -- Me \\\\//// \\XX// Greg Harp greg@ccwf.cc.utexas.edu
a665@mindlink.UUCP (Anthon Pang) (07/23/90)
In msg <13381@cbmvax.commodore.com>, daveh@cbmvax.commodore.com (Dave Haynie) writes: > In article <1990Jul20.172301.6908@watdragon.waterloo.edu> > rbharding@trillium.uwaterloo.ca (Ron Harding) writes: > > > Just imagine the possibilities if this is do-able! There are > quadrillions > >of cards for the IBM PC in the world. There are only a handful of Zorro > >cards. With this card, you could have internal modem cards, fax modems, > >extra video cards (VGA or whatever), any network card (Ethernet, Token- > >ring, Arcnet, etc), A/Ds and D/As. > > But there certainly are quite a few good IBM > cards out there. This has at least the potential of ASDG's Twin-X card, > probably more potential if it also works in an A2000 (eg, more PC slots > available). I've been a fan of this idea for years, and think it has > definite > commercial potential, expecially if whomever builds it can write some Amiga > device drivers for some of the more popular PC plugins. This sounds just like the AX-S Expansion System (vaporware?) that Spirit Technology Corp has been "announcing" for months. See page 138 of the 1990 Spring/Summer Amazing Computing Buyer's Guide...reprinted without permission: A hardware adaptor/interpreter that interfaces the Amiga Bus Structure/Expansion Port to the PC industry's PC/XT and AT Bus standars. AX-S Interface Board allows Amiga and AmigaDOS to utilize the low cost cards available for PC/XT and AT systems. AX-S connects Amiga's Bus/Expansion Port to a chassis with a heavy duty 200W power supply, ventilation fan, 7 plug-in slots, 6 PC/XT-AT bus slots and one OCTABYTE MB RAM expansion slot, multiple peripheral drive bays, hard drive power connectors, and an optional power cord for A500. Included with the chassis motherboard is the AX-S Interpreter board with DMA controllers, InterRupT (sic) controllers DATA buffers and Amiga Bus to PC/XT-AT Bus buffer drivers. Price unavailable. I think Spirit Tech can still be reached at: Sprit Technology Corp 220 W. 2950 S. Salt Lake City, UT 84115 (201) 307-9099 / FAX (201) 307-9404
daveh@cbmvax.commodore.com (Dave Haynie) (07/24/90)
In article <1990Jul20.172301.6908@watdragon.waterloo.edu> rbharding@trillium.uwaterloo.ca (Ron Harding) writes: >If CBM made a 286- or 386-based board with at least EGA graphics, things >might be different... They do make a '286 board, but it's not supporting EGA display modes, only MDA or CGA, at present. Of course, it seems to me that you're far more concerned with using these free network cards than what kind, if any, MS-DOS machine you wind up with. So a cheap enough Bridge Card would serve your stated purpose. Of course, that Bridge Card, or whatever solution you come up with, should cost less than the Commodore-Amiga Arcnet or Ethernet card you could buy instead. > What we are thinking of is a bus-adapter board which uses the >Bridgeboard slot to connect the IBM slots to the Zorro bus. The primary >function of this board would be to map the IBM bus's 1Meg memory space >into one of the many unused Megs of the Zorro address range. It would >also have to map the IBM's 64K io space into another Zorro range. That's something we've been proposing for years. It's called a "dumb" bridge card; basically just a bus translator to go between Amiga and PC/AT. No one has yet publically admitted to having built one, but it could certainly be done. >Which ranges of the Zorro space are used could be set by switches, or maybe >even Autoconfig. If you're building something to go in the 3000, it had BETTER be autoconfig; some of the "tricks" you could get away with on the 2000 bus are no longer possible. > We have not resolved some issues yet. Unfortunately, the Amiga Hardware >Reference does not describe either Zorro or the 1000's expansion slot >($%#^#%@%#!!). Unfortunately, the first edition of the Hardware Reference Manual was done before they had finished the Zorro specifications. You can order these from CATS today; currently the best book for Zorro II is the "A500/A2000 Technical Reference Manual". Zorro III specifications are much more complete, but I don't think they quite have a handy book for that just yet. > - The IBM bus provides 6 or so interrupt request lines. We're pretty > sure that it would not be hard to use switches to map the IBM's 6 IRQ > (or at least the ones that are in use) lines to some unused Zorro > interrupt request lines. PC-bus interrupt lines can't be shared. So the simplest thing you could do is wire-OR them together onto one of the Amiga lines. A single 74LS05 could do this for you. > - The IBM bus provides 3 DMA channels. Is it possible to map these to > Amiga DMA channels just like the interrupts? DMA is not essential > for most IBM cards anyway, but wouldn't hurt. IBM DMA channels aren't real DMA like the Amiga, just control lines for the DMA controller on the PC. You could probably put such a DMA controller on this card; even give it access to both the Amiga and PC buses. A cheap 16 bit microcomputer might be able to do the job more flexibly. > - Many cards for the IBM PC are very slow. The Nestar is probably one > of them. In fact, some original PC cards are so slow that they won't > even work in an AT, since the shortsighted designers of them didn't > give the option to generate wait-states. It was actually IBM who was short sighted. They never wrote a specification for the IBM PC bus. So designers building cards for this bus never had a clue that some day IBM would run it much faster and expect everything to still work. If I cranked up the Zorro II bus to 10 or 12MHz from its current 7.09/7.16 specification, you would see all kinds of stuff break. Proper expansion buses include specifications that tell you exactly what to expect in any legal backplane. Any machine with a CPU faster than the bus must compensate for this, not the other way around. You can find examples of this done correctly in the Amiga 3000 or any Mac II. > We don't plan on using any hard-disk controller boards, so blazing > performance is not a concern. It should be acceptable to have the > bus-adapter automatically throw some switch-selectable number of > wait-states into every IBM bus access. That's certainly possible, and a good idea. However, be careful with it; these wait states could unduely drag down your machine's performance. A card with too many wait states can time out the bus on the A3000. > > - Any IBM cards we will be concerned with are 8-bit. The 68030 seems to > have special instructions for dealing with 8-bit peripherals ( the > MOVEP instruction, for example). I don't remember offhand whether or > not the IBM slots in the 2000 or 3000 are 16-bit long-slots or not. If > so, then there may be special challenges. The PC slots in the A3000 are AT-style slots. The 68030 does have some special instructions for dealing with peripherals like this, as I recall. But the Zorro II bus is in fact a 16 bit bus; it doesn't dynamically resize like the 68030 bus. So if you're planning to treat the PC bus space as contiguous memory, you'll have to do 8->16 and 16->8 bit funneling when necessary to map the whole thing as 16 bit memory. This shouldn't be very difficult to do. > Just imagine the possibilities if this is do-able! There are quadrillions >of cards for the IBM PC in the world. There are only a handful of Zorro >cards. With this card, you could have internal modem cards, fax modems, >extra video cards (VGA or whatever), any network card (Ethernet, Token- >ring, Arcnet, etc), A/Ds and D/As. Actually, I think you can get everything you mention, except for VGA cards and token ring networks, for Amigas now anyway (OK, the only FAX attachment I know of goes via RS-232). But there certainly are quite a few good IBM cards out there. This has at least the potential of ASDG's Twin-X card, probably more potential if it also works in an A2000 (eg, more PC slots available). I've been a fan of this idea for years, and think it has definite commercial potential, expecially if whomever builds it can write some Amiga device drivers for some of the more popular PC plugins. >Ron Harding | Nuke'Em: Get them before they get you! -- Dave Haynie Commodore-Amiga (Amiga 3000) "The Crew That Never Rests" {uunet|pyramid|rutgers}!cbmvax!daveh PLINK: hazy BIX: hazy The Dave Haynie branch of the New Zealand Fan Club
galpin@ucscb.UCSC.EDU (Dan) (07/24/90)
In article <2589@mindlink.UUCP> a665@mindlink.UUCP (Anthon Pang) writes: >In msg <13381@cbmvax.commodore.com>, daveh@cbmvax.commodore.com (Dave Haynie) >writes: >> In article <1990Jul20.172301.6908@watdragon.waterloo.edu> >> rbharding@trillium.uwaterloo.ca (Ron Harding) writes: >> >> > Just imagine the possibilities if this is do-able! There are >> quadrillions >> >of cards for the IBM PC in the world. There are only a handful of Zorro >> >cards. With this card, you could have internal modem cards, fax modems, >> >extra video cards (VGA or whatever), any network card (Ethernet, Token- >> >ring, Arcnet, etc), A/Ds and D/As. > >This sounds just like the AX-S Expansion System (vaporware?) that Spirit >Technology Corp has been "announcing" for months. See page 138 of the 1990 > >I think Spirit Tech can still be reached at: > Sprit Technology Corp > 220 W. 2950 S. > Salt Lake City, UT 84115 > (201) 307-9099 / FAX (201) 307-9404 The Spirit people were demoing this beast at AmiEXPO Santa Clara last year. There apparently are two models.. one that gives you the case, slots, power supply, etc.. for the A500. This is the one that they had at AmiEXPO. The other model supposedly fits inside the A2000 and allows the use of IBM PC peripherals in the bridgeboard slots. As I remember, the list price for the 2000 compatible board was supposed to be around $255. Both products were set to come with "standard" device drivers for hard drive interfaces, serial ports + internal modems, and some sort of system where the end user could create their own driver for a board not directly supported. I haven't heard anything of this since. -Dan -- ****************************************************************************** * Amiga // * Short (TM) Signature * DISCLAIMER: * * \\ // * galpin@UCSCB.UCSC.EDU * This space reserved for a * * \X/ Only* COMP. QUOTE: Only time will tell* clever disclaimer someday. * ******************************************************************************
derhak@cs.utah.edu (Maxim Derhak) (07/25/90)
In article <13381@cbmvax.commodore.com> daveh@cbmvax (Dave Haynie) writes: >That's something we've been proposing for years. It's called a "dumb" >bridge card; basically just a bus translator to go between Amiga and >PC/AT. No one has yet publically admitted to having built one, but it could >certainly be done. > But it has been done. Spirit Technologies has developed such a card. It's called the AX-S hardware interface, adapter, interpreter. Last weekend a representative came to our users group and showed it off. Currently it works by connecting to the bus on a 1000/500, and connects to a seperate PC case which has an AT bus. They have developed a bridge type card for this system which coverts signals back and forth. They are working on getting the card to work in a 2000. In the case is also an extra Amiga Slot for adding memory and such (They have an octabyte board that goes on the amiga side of the expansion cabinet.) In their pamplet they openly say that this is not a amiga expansion cabinet to give 2000 zorro slots. Its just an expansion to an ibm bus, without the ibm cpu. They are developing an AX-S Resource Library for making drivers, and from the docs it appears that they are willing to provide it to developers. For more information people can call Spirit at 1-800-433-7572, or write to Sprit Technology 220 West 2950 South SLC, Utah 84115 Please note that I have nothing to do with Spirit Techonlogies, I am just repeating what I heard at the meeting. Please contact them with any questions you might have. > >-- >Dave Haynie Commodore-Amiga (Amiga 3000) "The Crew That Never Rests" > {uunet|pyramid|rutgers}!cbmvax!daveh PLINK: hazy BIX: hazy > The Dave Haynie branch of the New Zealand Fan Club Max Derhak ========================================================================== Lekarz THE //\/\ //| \ / # Max Derhak (derhak@cs.utah.edu) :^> od \\ // \ //-| X # After all is said and done, a heck of Raju! \X/ \// | / \ o a lot more is said and done. - Murphy
erd@giza.cis.ohio-state.edu (Ethan R Dicks) (07/25/90)
In article <13381@cbmvax.commodore.com> daveh@cbmvax (Dave Haynie) writes: >In article <1990Jul20.172301.6908@watdragon.waterloo.edu> rbharding@trillium.uwaterloo.ca (Ron Harding) writes: >> What we are thinking of is a bus-adapter board which uses the >>Bridgeboard slot to connect the IBM slots to the Zorro bus. The primary >>function of this board would be to map the IBM bus's 1Meg memory space >>into one of the many unused Megs of the Zorro address range. It would >>also have to map the IBM's 64K io space into another Zorro range. > >That's something we've been proposing for years. It's called a "dumb" >bridge card; basically just a bus translator to go between Amiga and >PC/AT. No one has yet publically admitted to having built one, but it could >certainly be done. The WEDGE for the A1000 and A500 does it. It does not autoconfigure, but it does map PC/XT I/O space into Amiga memory space ($EA0000 by default) I have a multi I/O card and an MFM disk controller on my WEDGE1000, and if I ever get the time, I will be writing a device driver for the GAMEIO and PARALLEL ports on it. It cost less than $40 for 2 serial, 1 parallel and an analog game controller. Yes these things are available for the Amiga, but due to the economy of scale, they are cheaper for the IBM-PC. Jim Brooks, who built the WEDGE hardware said that he couldn't generate much interest in them because people aren't driven by neat hardware, but by results. I have had a Western Digital style PC/XT disk controller on my A1000 since 1987. I get about 120Kb/sec under FFS. It doesn't blaze, but it isn't DMA. I paid less than $400 for new 20Mb drive, WEDGE and Western Digital WX-1 in 1987. The cheapest 20Mb SCSI drive and controller were at least $650 at the time. It still works. I use it for hours every day. Since I still have my A1000, I see no need to replace it. I, too, would like to see a PC/XT or PC/AT bus adapter for the Zorro bus. If there have been one, I probably would have migrated to the A2000 from the A1000. Instead, I bought a Rejuvinator, keeping another infernal dinosaur up and running. One of the main advantages a bus adapter is the ability to have networking hardware and a hard disk for little outlay. Cheap extra ports are really nice too; how much is the multi-serial port board from C-A or ASDG? I realize that you are getting software with the hardware, but the hardware isn't cheap to start with. The cost of a PC/XT Ethernet card is around $200. A second serial port is about $20. A disk controller is about $50. Add it up... under $300, just add a bus adapter and a hard disk. How much performance do *you* really need? A person who bought an Amiga to do wordprocessing and to use a database program and other mundane tasks isn't really going to scream about the difference between 600Kb/sec and 200Kb/sec on hard drive access. What they see is that if they click the icon, a few seconds later, they can edit their file. If most users could save several hundred dollars in expansion hardware, they would probably be willing to accept a bit of performance degradation. So... the $64 question is... "Would it really sell?" -ethan >>Ron Harding | Nuke'Em: Get them before they get you! > >-- >Dave Haynie Commodore-Amiga (Amiga 3000) "The Crew That Never Rests" > {uunet|pyramid|rutgers}!cbmvax!daveh PLINK: hazy BIX: hazy > The Dave Haynie branch of the New Zealand Fan Club -- Ethan R. Dicks | ###### This signifies that the poster is a member in Software Results Corp| ## good sitting of Inertia House: Bodies at rest. 940 Freeway Drive N. | ## Columbus OH 43229 | ###### "You get it, you're closer."
elec140@canterbury.ac.nz (07/25/90)
In article <1990Jul20.172301.6908@watdragon.waterloo.edu>, rbharding@trillium.uwaterloo.ca (Ron Harding) writes: > ... > > This is getting a bit long. Has anyone out there considered the > challenges of this? If you've already built such a beast, we'd love to hear > about it. On the other hand, if you know of some reason why it's not > possible, well, who asked ya, anyway? > > ============================================================================= > Ron Harding | Nuke'Em: Get them before they get you! > rbharding@trillium.uwaterloo.edu | Another quality home game from Butler Bros > ============================================================================= -- I have made a small board to plug into my Amiga 500 which provides me with one IBM (8 bit) slot. I designed it so that I could plug an IBM hard disk drive into my Amiga. (IBM hard disks are cheaper than any Amiga disk drive.) Other cards are probably just as easy to interface. I didn't need to worry about emulating the complete IBM interface since I only needed the I/O space and hence no memory space. Also the way the hard disk card is, I didn't need a DMA chip, but had the processor do the work. As for speed, I didn't do anything! When IBM XT's get Turbo'd to 8MHz they do nothing for bus speed, and since the Amiga is only ~7 MHz I decided to do nothing as well. The interface is quite simple and only uses three chips. (none of this autoconfig stuff!). An eight bit comparator (74HCT688) is used for address selection, with its enable line connected to /AS. The /A=B output is then ORed with R/W to provide /IOW and ORed with not R/W to provide /IOR. The /AS was also connected directly to the /ALE on the IBM side (this is not quite the same, but has the falling edge in the same place of the cycle). For the interrupts and DMA signals, I ORed these together (remember - IBM has tristate active high interrupts and DMA request signals - this is why you can't share interrupts on an IBM). Since these signals are tristate when not active, pull down resistors (1K8's) were used to make them inactive when not in use. Also reset is provided by simply inverting the /RESET line. Only eight data lines are connected (D0-D7), and the address lines A1-A10 are connected to the IBM's A0-A9 and all other IBM address signals were tied to ground. This means that the address space which is mapped appears at ODD locations through memory (accessing even locations will select the card, but the processor will miss the data). On the software side - I have a device driver for the Hard Disk which although probably not completely bug free, does the job. I have been using it now for two months without any worries. Of course its not autoboot, but then I have only just upgraded to KickStart 1.3 now anyway. When an interrupt occurs, the software decides whether it was for DMA or an IRQ, and if it was DMA it then reads the entire sector off the disk through one of the I/O addresses. By using this DMA line instead of polling the controller card the processor is free to get on with other jobs in the system. ********************************************************* Mark Tomlinson Postgrad - Elec Eng Dept Canterbury University Christchurch, NEW ZEALAND E.MAIL: Tomlinson@elec.canterbury.ac.nz P.S. Please post or email to above address as someone else posted this for me. What's a disclaimer anyway?
billsey@agora.uucp (Bill Seymour) (07/25/90)
In article <1990Jul20.172301.6908@watdragon.waterloo.edu> rbharding@trillium.uwaterloo.ca (Ron Harding) writes:
:
: My roommate and I have access to free Nestar Arcnet cards for the IBM
:PC. We will both be getting Amiga 3000s very soon (my first Amiga, he's
:replacing his 1000). We have been considering possible ways to use the
:Nestar cards in the Amigas.
:
: We don't consider the Bridgeboard an acceptable option. It's too
:expensive, and who wants an 8086-based MS-DOS machine, anyway? If CBM
:made a 286- or 386-based board with at least EGA graphics, things might
:be different...
:
: What we are thinking of is a bus-adapter board which uses the
:Bridgeboard slot to connect the IBM slots to the Zorro bus. The primary
:function of this board would be to map the IBM bus's 1Meg memory space
:into one of the many unused Megs of the Zorro address range. It would
:also have to map the IBM's 64K io space into another Zorro range. Which
:ranges of the Zorro space are used could be set by switches, or maybe even
:Autoconfig.
:
: We have not resolved some issues yet. Unfortunately, the Amiga Hardware
:Reference does not describe either Zorro or the 1000's expansion slot
:($%#^#%@%#!!). The issues we are concerned about are:
:
: [Bunch of good thoughts on designing this...]
:
: Just imagine the possibilities if this is do-able! There are quadrillions
:of cards for the IBM PC in the world. There are only a handful of Zorro
:cards. With this card, you could have internal modem cards, fax modems,
:extra video cards (VGA or whatever), any network card (Ethernet, Token-
:ring, Arcnet, etc), A/Ds and D/As. All sorts of stuff. You'd have to be a
:hacker-extraordinaire to get a lot of it working, but then you are reading
:this newsgroup, aren't you?
:
: This is getting a bit long. Has anyone out there considered the
:challenges of this? If you've already built such a beast, we'd love to hear
:about it. On the other hand, if you know of some reason why it's not
:possible, well, who asked ya, anyway?
There are a number of small implementations of this type out there.
Look at things like Wedge and that new goody from Spirit. Nothing I've seen
that's quite as flexible as what you're looking at though.
There is quite a bit of interest out there in hooking up ISA cards
to the Amiga though, we've sold a lot of our AM200A prototyping card, just
because of the ISA connectors on it. If you get this all working, you'll
have to release the design in the public domain so we can sell even more! :-)
Get the A500/A2000 Technical Reference Manual from CATS. That has the
best documentation on the Zorro II bus. It should answer pretty much any
question you might have about the Amiga end of the thing.
:=============================================================================
:Ron Harding | Nuke'Em: Get them before they get you!
:rbharding@trillium.uwaterloo.edu | Another quality home game from Butler Bros
:=============================================================================
-Bill Seymour ...tektronix!reed!percival!agora!billsey
=============================================================================
Bejed, Inc. NES, Inc. Northwest Amiga Group At Home Sometimes
(503) 281-8153 (503) 246-9311 (503) 656-7393 BBS (503) 640-0842daveh@cbmvax.commodore.com (Dave Haynie) (07/26/90)
In article <82425@tut.cis.ohio-state.edu> erd@giza.cis.ohio-state.edu (Ethan R Dicks) writes: >In article <13381@cbmvax.commodore.com> daveh@cbmvax (Dave Haynie) writes: >>In article <1990Jul20.172301.6908@watdragon.waterloo.edu> rbharding@trillium.uwaterloo.ca (Ron Harding) writes: > >>> What we are thinking of is a bus-adapter board which uses the >>>Bridgeboard slot to connect the IBM slots to the Zorro bus. >>That's something we've been proposing for years. It's called a "dumb" >>bridge card; basically just a bus translator to go between Amiga and >>PC/AT. >The WEDGE for the A1000 and A500 does it. It does not autoconfigure, but >it does map PC/XT I/O space into Amiga memory space ($EA0000 by default) I have heard about the WEDGE, but it's not a correct or complete solution. Not being an autoconfig card, it is not a Zorro II card and may not work in all backplanes. And it can easily cause conflicts with other cards. The other thing is that it only maps I/O, not PC memory as well. While that's certainly better than nothing, there are quite a few interesting things for the PC bus that are memory rather than I/O mapped. Also, as I understand it, the WEDGE is not a completely general purpose bus translator, but designed for a subset of IBM cards, mainly (though not exclusively) to get at the el-cheapo PC-XT ST-506 controller cards. Of course, a good percentage of the cards out there are only simple 8 bit cards, so perhaps that's not much of a problem. >I have had a Western Digital style PC/XT disk controller on my A1000 since >1987. I get about 120Kb/sec under FFS. It doesn't blaze, but it isn't DMA. >I paid less than $400 for new 20Mb drive, WEDGE and Western Digital WX-1 in >1987. The lack of DMA isn't your only problem. Assuming the WEDGE does a fairly efficient job of bus conversion, you're still talking to a slow, 8 bit card. And the disk drive is probably about as slow as they get -- the 20MB Western Digital IDE drives I've seen sport a seek of about 80ms. Decent 16 bit non-DMA controllers for the Zorro II bus with decent drives attached can give you 500kB/s+. Still, you buy a hard disk not only for speed, but capacity. >One of the main advantages a bus adapter is the ability to have networking >hardware and a hard disk for little outlay. Of course, someone must write the driver code. If you get the WEDGE and the recommended XT drive, you're OK. If you're planning to add a PC bus Ethernet card and actually do something useful with it, you have a great deal of work on your hands at present -- the software it comes with won't be any use to you. >Cheap extra ports are really nice too; how much is the multi-serial port >board from C-A or ASDG? I think the A2232 lists for about $50 a port. I don't know what they actually sell for. Of course, the A2232 also has its own CPU to keep the overhead of that card fairly reasonable; a dumber card might go for less. >How much performance do *you* really need? Me? More that we'll be seeing this year, I assure you. But every generation is getting closer. >A person who bought an Amiga to do wordprocessing and to use a database >program and other mundane tasks isn't really going to scream about >the difference between 600Kb/sec and 200Kb/sec on hard drive access. That's true. There are plenty of folks who were happy with C64s and floppy disks. A cheapo hard disk at any likely speed will keep lots of people happy, and you certainly don't need 180 Megs (what I have here) to support a little text editing. >So... the $64 question is... "Would it really sell?" The other 1/2 of the "dumb bridgecard" issue is support of the high-end or niche markets. There are boards you might use in a lab environment or other strange places that you can only get on PC bus. >-ethan -- Dave Haynie Commodore-Amiga (Amiga 3000) "The Crew That Never Rests" {uunet|pyramid|rutgers}!cbmvax!daveh PLINK: hazy BIX: hazy The Dave Haynie branch of the New Zealand Fan Club
<LEEK@QUCDN.QueensU.CA> (07/27/90)
> In article <82425@tut.cis.ohio-state.edu> erd@giza.cis.ohio-state.edu (Ethan R >Dicks) writes: >In article <13381@cbmvax.commodore.com> daveh@cbmvax (Dave Haynie) writes: >>In article <1990Jul20.172301.6908@watdragon.waterloo.edu> >rbharding@trillium.uwaterloo.ca (Ron Harding) writes: >> > >I have had a Western Digital style PC/XT disk controller on my A1000 since >1987. I get about 120Kb/sec under FFS. It doesn't blaze, but it isn't DMA. >I paid less than $400 for new 20Mb drive, WEDGE and Western Digital WX-1 in >1987. According to both ALF and Palomax people, OMTI controllers are one of the better ones in terms of performance vs price. OMTI RLL controller with Palomax can get about 250K/sec and 500K/sec with OMTI MFM performance vs 100K/sec read speed over a equivalent Western Digital... The OMTI controller 5527 (RLL drive) can do 1:1 interleave on a XT and it is about $100 Canadian ($80 U.S.) which is not much more of what Western Digital ask for a controller that can only handle 3:1 interleave. In another word, lower end Western Digital HDC is a dog. (Won't say the same for their higher end stuff as I have never played around with them.) > >-ethan K. C. Lee
jms@tardis.Tymnet.COM (Joe Smith) (08/11/90)
In article <1990Jul20.172301.6908@watdragon.waterloo.edu> rbharding@trillium.uwaterloo.ca (Ron Harding) writes: > What we are thinking of is a bus-adapter board which uses the >Bridgeboard slot to connect the IBM slots to the Zorro bus. The primary >function of this board would be to map the IBM bus's 1Meg memory space >into one of the many unused Megs of the Zorro address range. It would >also have to map the IBM's 64K io space into another Zorro range. [Description of many features of the board deleted.] Don't forget about the software required to make those IBM boards run. Many boards designed to plug into a PC have their own ROM's, which are designed to be executed by the 8088 CPU. This means that it takes more than simply installing a board into a PC/AT slot with a "dumb-bridgeboard". Some code in the 68000 needs to be executed to initialize the board. I expect this would require either having a custom INIT file for every IBM-PC board that can be plugged in to this system, or a "Soft PC" type program to emulate the 8088. The hardware is doable, just don't forget the software complications. -- Joe Smith (408)922-6220 | SMTP: jms@tardis.tymnet.com or jms@gemini.tymnet.com BT Tymnet Tech Services | UUCP: ...!{ames,pyramid}!oliveb!tymix!tardis!jms PO Box 49019, MS-C41 | BIX: smithjoe | 12 PDP-10s still running! "POPJ P," San Jose, CA 95161-9019 | humorous dislaimer: "My Amiga speaks for me."