Nezgar

If you haven't already seen, in this thread is a PCB to install the 2x6810's fully solderless/reversable... (though Still likely need to solder to change the Mask ROM/EPROM config jumpers) I have some bare PCB's as well as fully assembled including eprom if you're interested in that, or you can order the PCB directly yourself using links from that thread:

The world sending electronics recycling to China has resulted in them selling it all back to us now. I also buy all my EPROMs this way, and some are fake/rebranded (2764--27512 have a "chip ID" the programmer can read to help reveal the TRUE brand) -- and usually most work, maybe 1 out of 10 are bad... OK for the discount. I recently took a bet on a large batch of 6810 SRAMs, but all of them were bad or fake so I lost out on that one.

Exactly. The 4xOS board has 2 pull-up resistors (circuit designers choice/preference for pull-up or down I guess, doesn't really matter), so the middle "not connected" switch position results in a "high" status for the 2 address lines. (resulting in the "fourth" bank on a 27512) Up or down would select bank 2 or 3, with bank 1 inaccessible. The 3 terminals of a 3-way switch would be wired so that the center pin goes to ground (one of either the two inner-facing pins of the 2 double-pin jumper blocks) and the outer terminals wired to the outer pins of SW1/SW2 in that board as. For a basic switcher using the retro innovations 2364 adapter it's the same idea: 3-way switch terminals go to 2 address lines and middle pin to ground. (the 4 through holes in the corner) -- this PCB has spots for 3 pullup resistors, but for 1 3-way switch you would technically only need 2...

That mod can easily select between three OS's on a 27512 with a 3way switch, just 1 of the OS's would go unused/inaccessible. Same goes for the 2364 adapter PCB to switch between three BASIC ROM's with a 27C256 - leaving one unused.

Sorry I re-read what you typed as soon as I hit post and realized you meant YOUR board supported both. That's great! Reminds me of the AtariMax 32-in-1 board for the OS which is fancy because it allows switchless software selection of OS... APE Warp+ OS Upgrade Module (atarimax.com) What switching method are you planning to use to chose between the OS's you can fit on a SST39SF010 (I believe up to 8x16KB=128KB?)? For multiple BASIC ROM's, I've been using this PCB - again using older form factor chips which may be harder to obtain as you say: 2364 Adapter - RETRO Innovations (go4retro.com)

I think this "feature" of the 600XL applies to the BASIC ROM socket, not the OS ROM socket, which is always 28 pins, 27C128 compatible.

Why limit yourself to one? With this simple PCB, you can program an eprom with 2 or 4 OS's and with a switch you can activate whichever OS you like. Original for compatibility, OmniView 80 (even better choose Omnivew XL or XE) for 80 columns, and 2 more (ie an OS patched with HSIO routines, and maybe BOSS X2 V2 for other 800 game compatibilitiy. (There are dozens of alternatives....) Here is an example open source PCB to do this solderlessly: DIY 4xOS Switch. I have a few onhand if you're looking for one already assembled... But yes, if your 600XL still only has 16KB, upgrading to at least 64KB is the first order of business... PS: OmniView and OmniMon to do not preserve PBI routines.

Sorry for delayed response - PM sent!

As @BillC mentioned, there is only one very rare mod that enabled double-density on the 810 - I'm very curious if you could confirm the board that is in your drive, and maybe post some pictures to help. I am particularly interested to compare the firmware ROM against that dumped from the only other one known to exist currently. If you are not immediately willing to open the RF shield, there are some utility disks specific to the NCT Turbo 810 here: https://atariage.com/forums/topic/291937-neanderthal-computer-things-810-turbo/ Pictures of the PCB here: https://archive.org/details/Neanderthal_810Turbo/mode/2up Manual here: https://archive.org/details/810Turbo

Run the option 2) diagnostic. The result of the RAM test will show which version of the 1050 happy ROM you have: 'PASS' for v1 and 'Pass' for v2, or possibly a failure for any other modified version... I believe "laser" upgrades I've seen previously here on the AtariAge forums had the v1 ROM. V1 does not support the UltraSpeed protocol on power-up, and must be enabled with the utility disk. It also probably doesn't exhibit a bug where sectors are currupted with unbuffered single density disk writes.

At one point I toggled the partition name option and it caused all the partitions to become unreadable, since partition names cause each partition to incur a +1 sector offset. Maybe try toggling that?

Format in normal "skew" (the word "interleave" would be more correct) when the disk is going to be used in non-ultraspeed mode - ie with a stock 1050, or with an OS or other software that only operates in 19.2K mode. The modified firmware formats an interleave that's about 10% faster than other drives. In the case of single density, both are technically a 9:1 interleave, but optimizing the interleave to account for the space taken by the gap between the first and last sector of the formatted track. When you choose UltraSpeed skew, SpartaDOS uploads an alternate sector interleave to the drive and then issues a custom format command that is optimized for the reduced time that it takes to transmit a sector between the drive and the computer so that the next sector arrives at the read head sooner than a regular formatted disk. A regular single density disk is about 9:1 (the next sector is available after skipping 8 sectors), the "optimized" standard interleave is about 8:1, and a US Doubler ultraspeed single density disk is 5:1. An Indus GT syncromesh interleave is 4:1, and is too tight to be read at full speed on a US doubler, causing the drive to basically only be able to read 1 sector per rotation. Similar when reading a disk formatted with the "UltraSpeed" 5:1 interleave with a drive operating at regular speed - it will be a lot slower, reading only 1 sector per rotation. I believe all this does is allow use of the last sector of a disk by the file system. In the tradition of Atari DOS, the last sector of a disk was not usable by the file management system, and SpartaDOS I guess followed it. The post ICD/FTe releases of SpartaDOS from the SpartaDOS X Upgrade Project introduced this option in the formatter. SpartaDOS will try to engage the "UltraSpeed" protocol with all drives by default. You can tell the difference by the audibly higher-pitched and shorter sound of the sector transfer beeps. Since the US doubler has no track buffer, this will only help with the overall throughput with disks that have been physically formatted with the "UltraSpeed" interleave aka skew. It's a cool hack with minimal additional hardware which made it popular since it was cheap, but this is also where the more expensive enhancements like the Happy, Duplicator, Indus GT with Super-Synchromesh shined because their track buffer allowed maximum speed no matter the sector interleave of the disk...

Well, the 800 version is a prototype.

@Calab I made a patched US Doubler ROM that speeds up the stepper delay to timing similar to a Speedy 1050, and also replaced the format sector interleave tables for Enhanced Density (taken from Turbo 1050) and Double Density (taken from Percom AT-88). Note the original and this modified ROM are optimized for drives with a Tandon (made in Singapore) mechanism. https://atariage.com/forums/topic/158768-atari-1050-roms/page/3/?tab=comments#comment-4594602 The other 1050 variant, made in Hong Kong, has a World Storage Technologies mech, and uses an alternate phase encoding that will result in a 1/4 track misalignment if the ROM is mismatched. Here is a link to a patched US Doubler ROM for these drives. It provides a faster stepping rate equivalent to the original Atari ROM for these drives, as well as the proper phase encoding. I haven't yet made a patch of this so it will format faster ED+DD interleaves. https://atariage.com/forums/topic/156462-1050-roms/page/2/?tab=comments#comment-4060813 If you're interested in an assembled or unassembled 6810-doubler PCB I have a couple assembled and numerous unassembled here, or you can order your own from a fab. I really like this idea because it makes the upgrade completely reversible rather than permanently soldering two 6810 chips together. Details on that project here:

Can you take a better picture of the board from the top so the chip numbers are readable? Or just indicate what the leftmost chip there is... My guess is that PCB is either a clone happy or duplicator board, and since U8 has double-stacked 6810 chips, it may have also had a switch to toggle to run as a US Doubler compatible mode... I can see the EPROM is a 2764, which would be the size to house only a Happy or Duplicator Rom, not also the US Doubler ROM. Can you check if there is another ROM present in the U10 socket? As far as troubleshooting goes, if you have another 1050 I'd probably start by returning it to a stock configuration by swapping in an original ROM (U10) and 6507 CPU (U9) and possibly single 6810 SRAM (U8) to rule out the upgrade...

Says on the label of your OS chip "APE Warp+ OS 4-in-1" - so I guess it's an earlier version of the current "32-in-1" product. https://www.atarimax.com/warpos/documentation/ So my guess are some combination of: 800XL OS 800 OS 1200XL OS Warp+ OS

This effect seems like it could be done pretty easily with pre-rendered vertically short animation frames for the cog-wheels in GR.9 mode, and using simple DLI tricks to swap frames and repeat down the screen. The overlay text would presumably have to be done with PMG.

Official ICD source code is not "out there". However, there is a disassembly of unknown origin and limited usefulness due to lack of comments here: https://atariage.com/forums/topic/115434-new-indus-gt-firmware/?tab=comments#comment-1396039 I believe @phaeron did a disassembly as well, and his comments are usually stellar, which I can't find the post about at the moment. Keep in mind that the stock 1050 ROM works with the USD doubled-6810 SRAM installed, so it's just a matter of swapping the USD vs Stock ROM. you can put it on a single 2764 and install a toggle switch between the two ROMsand the drive itself can be left in the "Mask ROM" configiration too with an adapter like this: http://www.go4retro.com/products/23xx-adapter/

All versions of SpartaDOS merely print the directory entries in the order they are on disk. You can solve this with a utility called SORTDIR which sorts and rewrites the directory as per your specified preferences. I think it came in the 3.2 construction set, maybe it's in the SDX one too.

My first thought is this is the result of a custom/replaced OS... Checking some of my XL/XE OS's... OmniMon XL - BOOT ERROR OmniView XE - LOAD ERROR XL BOSS V1 - LOAD ERROR XL BOSS V2 - BOOT ERROR OSN XL - BOOT ERROR SuperMon '86 - BOOT ERROR Funny XL BOSS switched back to "BOOT ERROR" in V2...

There is literally only 256KB total in the system. 64KB + 192KB. Look at the motherboard in the original post - 8x256kbit chips. The chips on the additional PCB only contains logic chips. @Steverd - there is a slightly updated version of that memory tester available here: http://atari.sk/extended-ram-test-0-22-0-xram0220-xex/ For reference, here is what 0.22 looks like from a system of mine with an ICD Rambo 256K 800XL. I'm curious if the newer version presents differently that this on your system. I'm curious about the difference of missing row at $Ax vs $8x.

Thanks for the detailed clarification @reifsnyderb, much appreciated and much more coherent than my previous thoughts. With 32K provided by the 128k AS6C1008 SRAM chip ($0000-$3FFF & $8000-$BFFF) I guess technically 96KB of that chip goes unused. Then the 1024KB from the AS6C8008 SRAM provides 64 16KB banks at $4000-$7FFF, of which 1 would be considered the "base" RAM, plus 63 "extended" banks. so 32KB + 1024KB technically in hardware, or from the software perspective seen as 48KB of "base memory" plus 1008KB from 63 additional 16 KB banks, for 1056KB total. Got it! So I guess future ideas for consideration would be: a 52K mode, but this would have to disable Axlon banking. The $CFFF register supports up to 256 banks, so you could technically add 3 more MB for a 4MB max -- SpartaDOS X does support this.

Neato. Simcheck shows 32KB base memory, is it actually 48K, but 16KB occupied by a cartridge or maybe a hardware bug? Do you still need one more RAM module to fill $8000 through $BFFF? Or even up to 52K CFFF, but then that introduces potential for conflict with the axlon banking register... MEM /X also showing TOP $7FFF (32767) in your screenshots. Edit: I see now rereading you indicated the board only handles 32K of the memory map so that makes sense. I hope the last 16KB can still be made up with a module in the remaining empty slots. Also you mentioned 62 banks, but sparta indicates 63 banks. Sparta consumes one bank for disk i/o buffers and such, so that's why it says 63 banks/62 free. But help me understand as I think through this. If the board really has a total of 1024KB, that means that 16KB would need to be fixed mapped to $0000 through $3FFF, and $4000 through 7FFF base RAM would be "bank 0" but indeed there would only really be 62 more banks available. If SpartaDOS X or other ramdisks think there are 63, then there must be 1 unusable bank or shadowed due to the base 16K from $0000 to $3FFF?

I agree, but I imagine all it took was a customer to complain about data loss when removing a disk prematurely if this applied to buffered writes... maybe 3.1 was only offered to "those" customers. ?

Yes.... that is also my prime desired bug to fix.