Improved Sector Layout CX8111

[tschak909]

The big give away is the addition of the Grass Valley Analog board on the top of the drive mechanism.

 

-Thom

[+Nezgar]

How do you tell if your 810 is a rom b or c other than timing it? Do you have to open it up or can you do a peek from basic or something?

Without opening the drive, only way is to format a disk with the drive in question, and then compare the sound of sequential sector loading speed with the sound bites I posted earlier in this thread.

 

Or analyze the resulting skew with something like chip or archiver...

 

Rev E has 1 or more additional available SIO commands to upload small amounts of code to the drive you could test for with software, but I think that was mostly internal to Atari and not meant for the general public, but thankfully has been found

Edited December 17, 2017 by Nezgar

[_The Doctor__]

it's Atari, it always makes it to the general public... sometimes before it hits the shelf... sometimes 20 years later... but eventually......

[+hunmanik]

The Atari FAQ btw marks these as "announced but never shipped".

 

Note that I was trying to indicate that the retail box containing 5 of them never shipped (as far as I can tell).

 

Individual CX8111 disks are readily available because one each shipped with DOS 2.0S. (And also Home Filing Manager, and perhaps other titles.)

[Rybags]

Possibly those extra SIO commands are diag functions similar to what the 1050 has?

 

I'd check my 810 but it's a non responder... suppose given that I have the docs and a CRO that I should try and fix it.

[+Nezgar]

Not sure what the specific new command in the 810 rev E ROM is, but there is this mention of it in Mapping the Atari revised edition for XL and XE page 79/80:

 

Post from 2007 by ijor who looked at the disassembly of the Rev E on the net. Found some additional diagnostic codes, but it would be a stretch to allow 'selective formatting of disk sectors as written in Mapping... http://atariage.com/forums/topic/100254-disapointed-with-1050-disk-drive/?p=1220388

 

And back to regarding rev C - Some interesting excerpts from - "ANTIC VOL. 1, NO. 4 / OCTOBER 1982" https://www.atarimagazines.com/v1n4/upgradesavailable.html

 

810 ROM C

 

An 810 drive with ROM C and DOS 2.0 will offer improved performance in read and write operations between the 810 and the 400 or 800. ROM C causes diskettes to be formatted with an improved sector layout which is more efficient than that used by earlier 810 control ROM's.

 

ROM C is automatically included in drives manufactured after October, 1981. Atari's Regional Service Centers will perform the upgrade on out-ofwarranty units for $53.56 ($8.56 in parts, $45.00 in labor). 810 units still in the 90-day warranty period will be upgraded free of charge, on request.

 

810 Data Separator Board

 

The Data Separator Board for the 810 improves the drive's ability to distinguish between data pulses and clock pulses on the disk. This is necessary in part because of the variations in the characteristics of different diskettes. The data separator lowers the chance of a misread from the disk.

 

Data separator boards have been a standard part of all drives produced since October, 1981. Older drives that are out-of-warranty may be upgraded at an Atari Regional Service Center for a charge of $135.61 ($40.00 Iabor, $95.61 parts).

 

The HCD Factory Authorized Service Centers will also perform these upgrades on request, although their prices may differ from the RSC's. Any 810 still in the warranty period will be upgraded free of charge.

[tschak909]

and to think, Percom was selling data seperators at $45 a pop.

 

-Thom

[Tempest]

ROM C is automatically included in drives manufactured after October, 1981.

 

Data separator boards have been a standard part of all drives produced since October, 1981.

 

That helps. Now I can just look at the date on the bottom of my 810.

[pirx]

it was soooo good to have a drive with a track buffer ))

got 2 - Toms Multi Drive expansion for Indus GT clones and Toms 720 monstrosity.

[ijor]

810 ROM C

 

An 810 drive with ROM C and DOS 2.0 will offer improved performance in read and write operations between the 810 and the 400 or 800. ROM C causes diskettes to be formatted with an improved sector layout which is more efficient than that used by earlier 810 control ROM's.

ROM C is automatically included in drives manufactured after October, 1981.

Somebody was going to dump 810 rev B not too long ago. A pity that seems he never did. That ROM version is still missing.

 

Anybody has an early 810 with rev B firmware?

[+Nezgar]

Somebody was going to dump 810 rev B not too long ago. A pity that seems he never did. That ROM version is still missing.

 

Anybody has an early 810 with rev B firmware?

 

I found this thread/post from 2016 http://atariage.com/forums/topic/85478-810-rom-images/?p=3618778 where re-atari thought he might have a revision 'B' rom based on the part # but no dump yet. Dunno if he's still active, but maybe there's a chance he would mail the chip to someone who knows how to dump it.

 

Speculated that:

C011299B-03 was revision 'B'

C011299C-03 was revision 'C'

Edited December 19, 2017 by Nezgar

[Goochman]

How can one tell which revision they have?

[+Nezgar]

How can one tell which revision they have?

 

3 things to check, summarizing from this thread:

 

Listen for the 'slow interleave' sector loading sound of a disk after formatting in an 810, reference sound bites I attached to Post # 12 of this thread:

http://atariage.com/forums/topic/269694-improved-sector-layout-cx8111/?p=3844563

 

Lack of the Grass Valley Analog board on the top of the drive mechanism would be an indicator of a very early production drive that has never been upgraded, and is much more likely to have the earlier ROM.

 

Look for the part # on the ROM chip:

C011299B-03 may be the missing revision 'B'

C011299C-03 is revision 'C'

Edited December 20, 2017 by Nezgar

[KLund1]

Where is the 'Data Separator Board'? It is not the Grass Valley board? Is there pics of each?

So the 'best' stock 810 would be one with a Rom E and Data Separator board? Which drive mechanism, push button, or flip up, would be best for this?

[+Nezgar]

Grass Valley upgrade was for the analog power and r/w circuitry. From the Best website:

 

Atari Engineering Grass Valley 810 Analog Rear board upgrade set. New Rear 810 Analog Rear Power board, New Top Analog R/W board, New 10 Pin Jumper cable, Installation Instructions. Upgrades / Replaces the older Atari 810's with Single Power board that 100% Fails. See Atari 810 Tec tip below! CB101128 $35.00

 

A separate upgrade got you the Rev C ROM and the data separator board. Also quoting best:

 

Atari 810 New Sideboard Populated with upgraded plug in Data Separator board and the final version "C" version 810 OS Chip. (no RF Shield) This is a new drop in replacement Atari 810 sideboard for both the Tandon and MPI version Atari 810 Disk Drives. See Atari 810 Tech Tip below CA014834 $29.00

 

So.. Analog power board in back, Rom and data separator on side, and analog r/w on top. Rom C is the standard standard release, Rom E was 'leaked', so YMMV with that rom.

 

Good read here http://www.best-electronics-ca.com/8-bit_.htm- mentions early production tandon mechs also commonly had the door pins break

[+Larry]

Presume this is it...

 

 

[Tempest]

So are the 'garage door' push button style 810's the early models or the later models?

[+Nezgar]

Found an ebay auction ending Thursday that includes an 810 side board with a CO12499B OS ROM. If anyone is interested in acquiring it to dump in the name of preservation, shipping shows as $10 to someone the US vs $40 to me in Canada.

https://www.ebay.com/itm/122879327929

 

[Rybags]

The firmware Rom should have the same pinout as the 2K FP Rom for an 800... though not sure if the CS assignments are the same.

Possibly it could be copied by placing into the FP socket and booting a suitable program to dump it out... though while the FP is absent language and many other programs wouldn't work.

[+Nezgar]

I came across another interesting reference in Creative Atari, Page 195, in the section "Fast Format Chips" (Book dated 1983): https://www.atariarchives.org/creativeatari/Atari_DOS.php

...The C format is about 20% quicker than the B format, because the disk is laid out more efficiently. Disks that come from Atari use the C layout.

 

...A group of users in Chicago modified the B layout to what is called the Chicago layout. This layout is 30% quicker than the B format and indeed is 10% quicker than Atari's own C layout. However, a price is paid: the disks become rather sensitive.

Atari disk drives have difficulty maintaining a given rpm, which causes several problems, including lots of read-write errors. If you install the Chicago format, and your disk spins at more than 288 rpm, it will skip sectors, doing a complete spin between reads. This is quite slow and has a distinctive "Beepbeepbeep (pause) beepbeepbeep (pause)" sound. If you get this, check your disk.

I wonder if this supposed 'Chicago layout' is similar to the tight skew seen in the 810 Archiver/CHIP and USD, and if anyone knows anything further about that mod? I do personally recall a SD disk formatted in a 1050 USD missing some sector reads on an 810, could very well be the 810 RPM is slightly too fast, or the formatting 1050 was too slow. I'll have to test this some more.

 

 

Yet another consideration is that the difference between the B and C chips available from Atari does not consist solely of the formatting change. The chips are much different, and supposedly other improvements have been incorporated into the C revision. You may be missing out on these improvements if you install a Chicago chip.

 

Would be interesting to see if there are actually any differences between B and C other than the format skew.

[+Nezgar]

So are the 'garage door' push button style 810's the early models or the later models?

The cover of the 810 Disk Drive Operator's Manual ©1979 shows the push-button garage door style which I believe this is the more common MPI mech. The Tandon mech was used later, at least by June 83 ( reference: http://atariage.com/forums/topic/223137-810-disk-drive-differences/?p=2951285 )\

 

edit:

Wow, detailed history of the 810 including the ROM change, updated boards, and mech change in the 8-Bit FAQ 25 Nov 2017 - http://atari-800xl.com/faq/atari-8bit-faq.txt - Small Excerpt:

The 810 underwent several significant design revisions over the course of its

manufacture.

 

Original 810 Disk Drive (1980-1981, no Data Separator and "Pre-Analog")

- Micro Peripherals, Inc. (MPI) minifloppy diskette drive mechanism

...

In November 1982, the drive mechanism of the 810 Analog disk drive was changed

from MPI to Tandon. The Tandon version is known as the "810T Analog" disk

drive.

Edited December 26, 2017 by Nezgar

[ijor]

Found an ebay auction ending Thursday that includes an 810 side board with a CO12499B OS ROM. If anyone is interested in acquiring it to dump in the name of preservation, shipping shows as $10 to someone the US vs $40 to me in Canada.

 

I don't mind contributing for the sake of the ROM to be dumped. Note that it might require custom wiring.

[phaeron]

Unless I'm mistaken, the picture posted above is of an 800 personality (OS) board, not the 810 side board. The 810 side board in the auction has a C010299C ROM on it.

[+Nezgar]

Unless I'm mistaken, the picture posted above is of an 800 personality (OS) board, not the 810 side board. The 810 side board in the auction has a C010299C ROM on it.

Yup you're right, I totally spaced on the numbers, thanks for catching it. Up too late I guess.

Edited December 26, 2017 by Nezgar

[+Nezgar]

Visual evidence of the "CO11299B-03" ROM in a 2016 post by re-atari: http://atariage.com/forums/topic/85478-810-rom-images/?p=3619193

810 - side board - component side.jpg

 

Question to those who have successfully dumped an 810 ROM in the past, if this Rev B ROM is eventually located and dumped.. - How difficult would it be to burn it to a new EPROM in a manner that would work in an 810?