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Kaypro Advent RAMdisk questions

C

cfenton

Experienced Member
Joined
Jan 25, 2008
Messages
70
So I found some document along the lines of "Advent TurboROM theory of operation" in one of the archives, and it says that the code to initialize a RAMdisk (and even boot from, i believe) is entirely in the ROM chip. It also said, that the ramdisk interface only uses four bytes, 0x88-0x8B in the I/O space, with the following map:

88 = Bidirectional data
89 = Sector Count (6 low bits)
8A = Track Count (7 low bits, bit8 sets disk0/disk1)
8B = Status byte (determines ramdisk size)

This seems like it would be an extremely easy way to wire a hard drive into a Kaypro, and I was wondering if I understood the operation correctly:

1. The kaypro sets the track by writing to 0x8A
2. the kaypro sets the sector by writing to 0x89
3. the kaypro then reads (or writes) 0x88 128 consecutive times, reading/writing the entire 128 byte sector. A counter that's internal to the ramdisk increments on each read/write operation, incrementing the address lines of the ramdisk. This "pointer" gets reset to 0 every time the sector or track is set.

Can anyone that owns one of these (or just has used one before) confirm this? It seems like it would be pretty easy to build one of these, and if it natively supports 2 x 1 Megabyte ram drives, it would be pretty convenient.
 
If I am remembering correctly, I think they used the same, or VERY similar interface board, for the RAMDisk and for their own hard disk kit. It's on of those Z80 socket piggyback jobs. On my RAMdisk setup, the connector on the piggyback board is a 40-pin dual-row header, similar to the old-school IDE connectors. Of course, it's not IDE, I'm just saying the connector is the same.

Would make sense, too, because I think the Western Digital WD1002-HD0 has a 40-pin interface.

FYI, the Advent TurboROM support up to (2) 64MB hard disks using either the Advent HD setup, or the Kaypro HDD setup.

T
 
So I realize emulating an actual hard drive would be the best solution, but I don't really enjoy the thought of emulating the whole HDD controller chip. This ramdisk interface sounds dead simple, and I could whip it up in an FPGA in like 20 minutes (not including the time to physically wire it, of course). Will the Turbo-rom actually boot off of a RAMDISK, if it's the only disk present?
 
Not that I'm aware of - remember, it's RAM, and not backed up, so the TurboROM initializes and formats the RAMDisk on power-up. I think it can preserve between resets, but not a cold power-on.

T
 
RE: Kaypro 4 with Advent TurboRom

RE: Kaypro 4 with Advent TurboRom

Sharkonwheels said:
If I am remembering correctly, I think they used the same, or VERY similar interface board, for the RAMDisk and for their own hard disk kit. It's on of those Z80 socket piggyback jobs. On my RAMdisk setup, the connector on the piggyback board is a 40-pin dual-row header, similar to the old-school IDE connectors. Of course, it's not IDE, I'm just saying the connector is the same.

Would make sense, too, because I think the Western Digital WD1002-HD0 has a 40-pin interface.

FYI, the Advent TurboROM support up to (2) 64MB hard disks using either the Advent HD setup, or the Kaypro HDD setup.

T
Click to expand...

Hello Sharkonwheels,

I have a Kaypro 4 calls for Advent TurboRom V.3. Can you advice where I can get a boot disk?

Doug
 
Hello Doug,

1- Sharko hasn't been around for a while and I suggest you
send him an e-mail.........I have and he responds.

2- The link I have posted in another thread belongs to
Peter Dassow who is frequently available at cctalk. You might
want to contact him at his e-mail address or post your question
there. There are some hardcore Kaypro people there who might be
able to help you.

3- You can search in our beloved milkyway and try finding
the one and only.....Terry Yager.... our resident Kaypro guru
who has been offline for a while now, and talk some sense into him....

Best regards

ziloo :mrgreen:
 
Doug,

Just a couple of quick thoughts -

I responded to your cctalk email - I am more into Kaypro II and Microcornucopia upgrade, not Advent.

Also, I noted to search this site for more info.

I think the Advent Ramdisk is something else - in essence an external almost hard drive in capacity. They are old 2008 posts please note.

You are looking for just the chip on the main board by Advent I believe.

If you do a Google search I believe there is some Advent product still out there and they may have your version of the disk you need.

Correct me if I am wrong - anybody.

There is so much going on it is hard to keep track of it all.

Sorry for your frustration, but it comes with the territory for many reasons Doug.

That is why it is important to keep our Kaypro knowledge base on this site as up to date as possible to help all as we work thru all these issues.

So please report back on your progress.

Good luck !

Frank
 
RE: Kaypro 4 with Advent TurboRom

RE: Kaypro 4 with Advent TurboRom

1- Hi Ziloo

Thanks for your replies. I will do Sharko after I get hold of his email address. What is cctalk by the way I will also try Peter Dassow & Terry Yager.

2 - Hi Frank

Thanks for all your replies. I have followed your advice and keep on digging for more info. Basically, I am just looking for a boot disk to load programs. You are right that it may be an external almost hard drive in capacity. Upon my closer look it does have a 5"x5"circuit board full of chips attached to the side cover of the dual disk drives. It seems to me that may be a Ramdisk.

3 - Hi Chuck

Thank for your reply and the disk image. You are right that I am incapable of writing my own from the disk image. I don't have Window 98 machine any more I also I have not done that conversion before. I still hope someone could offer a hand.

Doug
 
Given (especially lately) the volume of off-topic posting on the cctalk list, perhaps cctech is a better choice (supposedly the same, but more on-topic). In fact, I'm not sure there's much difference. The conversation tends to have a heavy vintage DEC content, with perhaps less HP, Sun and SGI. Not inordinate amounts of PC/Apple, although recent events have changed the picture a bit.
 
Doug,

Some pictures would help of what you call a "ram disk" and even the chip, if that is what you are talking about.

I believe the Advent chips were very clearly marked as such with a white label over the chip + some other info possibly on the label.

There were a number of other products that were like the Microcornucopia upgrade, since it was so popular.

I think only " Microsphere " made a “ram disk”. It increased the ram from 64 K to up to 1 MB - a big jump in those days. I believe there were even directions to make your own “ ram disk, “ but that was very complex.

If I recall correctly, the “ ram disk “ was in an external black box about 6 “ x 8 “ that connected thru the printer port.

I think the “ ram disk “ might be very rare, since it was expensive at the time and I never heard many others using it.

Keep us informed - we are all learning all time !

Frank
 
RE: Kaypro Advent RAMdisk questions

Hello Frank,

The Advent Kaypro 4 is packed with several additional circuit card boards. I am afraid to take it apart before I can test it first. This version of
Kaypro does seem rare, so I try not disturb it or destroy it. The Ram disk issue need to wait until I got hold of another unit.

Regards,

Doug
 
I realize I started this thread ~12 years ago, but just so I don't leave anyone hanging - it really was that easy to make a RAM disk using an FPGA board. It only took a few lines of RTL, and the TurboROM automatically recognizes it and adds a 2MB "C:" drive upon boot. It works great!
 
cfenton said:
I realize I started this thread ~12 years ago, but just so I don't leave anyone hanging - it really was that easy to make a RAM disk using an FPGA board. It only took a few lines of RTL, and the TurboROM automatically recognizes it and adds a 2MB "C:" drive upon boot. It works great!
Click to expand...

Any chance of your providing details?
 
I used the version of this board that has 2MB of SRAM: https://www.micro-nova.com/mercury-2

1. Add the chips and 50-pin connector to my Kaypro 2/84 board so that it could interface to the hard drive expansion board
2. Wire a protoboard with a 50-pin connector that connects the Z80 I/O bus to the 5V-tolerant pins on the mercury 2 board.
3. The board/sector/track registers just make up the address for the SRAM. There is a 7-bit auto-incrementing pointer register that gets reset whenever you change the board/sector/track, and it increments every time you read or write the data byte.

I have some more parts en route that I'm going to try to use to add an SD card to emulate 2 x 56MB hard drives, and I added a Real48 FPU to speed up my Turbo Pascal code just for fun, as it's a pretty huge FPGA.
 
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