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Hi there,

 

I have had in the Eighties a special firmware (a patched original) for the 1050. When disks are formatted with these firmware, all disks (single and medium density) were read more faster on any 1050 without trackbuffer (e.g. w/o speedy or happy etc.) than normal. If I remember right, the "trick" was a new sector skew in the format tables.

 

Does anybody have these firmware? If so, please upload. Thanks.

 

Regards, Juergen

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No - no additional hardware. Just plug in a new 2532 eprom with the new, patched firmware.

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Hello 31336haxx0r

 

The US Doubler needs extra RAM, as the 1050 only has enough RAM for a 128 byte sector. IIRC 128 bytes are added, plus probably some hardware to select it. Plus the new EPROM.

 

Mathy

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Strange...

 

A few years ago I bought IIRC an ICD US DOUBLER... on ebay. It was 'a thing' that was glued into a small plastic case, which I had to put in the 1050 OS ROM socket. That was it... does this thing have that extra ram inside? I am not at home right now... I have to search for that thing.

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Hello Marius

 

I haven't really seen a US Doubler, IIRC, but I know I once found the code for the EPROM (don't ask me where I left it) and the instructions needed to build one ("unofficial" version :-) ).

 

Mathy

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US Doubler is 2 IC"s that are swaped out on a 1050, and a quick siolder wire patch depending which drive mechinizim you have. I did this a couple years ago on severu 1050's. They work great!.

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Strange...

 

A few years ago I bought IIRC an ICD US DOUBLER... on ebay. It was 'a thing' that was glued into a small plastic case, which I had to put in the 1050 OS ROM socket. That was it... does this thing have that extra ram inside? I am not at home right now... I have to search for that thing.

The ICD US Doubler hardware simply consisted of a replacement firmware/OS chip and the "plastic case" IC, which is just 2 6810Ps piggybacked with appropriate jumper connections to give a larger buffer necessary for DD operation. I've never tried it but just the US Doubler ROM might work for SD and ED formats since they may work without the larger buffer.

 

Below is a link with details of the USD stacked 6810P RAM module.

http://ftp.pigwa.net...USD RAM Mod.htm

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Hi,

 

thanks for all suggestions. But it´s not US Doubler (this one needs extra RAM). It was really only a new firmware, no need to solder or replace any other than the PROM/EPROM (ok, you´ve to change the zero ohm resistors to select EPROM usage, if the 1050 has a PROM on it).

 

Perhaps this one never circulated outside germany. A lot of people I have knew have use it in the mid eighties to get a little more speed, the Speedy 1050 wasn´t on the market and the Happy 1050 to much expensive and hard to get. When the Happy clones comes for cheap, this solution was not more needed any longer.

 

There was also a second solution with software, I did not remember if it was DOS 2.0 or DOS 2.5. It was a patched DOS, which writes new files backwards, e.g. the highest availible free sectors was used, then the next lower one and so on. When these disks are read with a normal 1050, then reading is a bit faster. But it only works with one density (don´t know if it was Single or Medium), the other density was much slower than normal.

 

If somebody find anything in these both facts, please let me know. Thanks.

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What the fast load is, is how the sectors are arranged on the disk. Normal single density was something like this 1,3,5,7,9,11,13,15,17,2,4,6,8,10,12,14,16,18

Fast load is 17,15,13,11,9,7,5,3,1,18,16,14,12,10,8,6,4,2.

There is a gap between last sector and first sector on each track that is almost a sector in length. In 2nd example, it would be between sectors 2 and 17.

Reading the fastload puts the sectors slightly closer together so drive waits a little less time for sector to come up.

I did read about it in the archiver manual i think it was.

Usd has fastload sector map built in.

 

James

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so actually is there a possibility to have a software fastload? which means you gonna format disc and put your custom loader in sector 0-3 to read the stuff faster but without to modifiy any hardware simply software driven?

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On an unmodified drive you can get speedup by reading the sectors in reverse order per track.

It's nothing mind-blowing, maybe a few % improvement.

 

No idea though how it would go on a modded drive where the disk is formatted with different sector skew - it'd probably slow down.

 

In the modern day it's barely worth worrying about - makes absolutely no difference if using SIO2xx devices, plus these days we tend to want file based games rather than volume based.

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So if you didn't use DD, then the Doubler (type) code should work? The only fly in the ointment is that there may be a code check in the Doubler to detect whether someone has the additional ram of the Doubler. If someone had "pulled its teeth" or wrote similar code, then that sounds like the device this thread is describing.

 

This is a bit like the 810 "Chicago" code/skew -- supposedly gave about another 8-10% boost over new Format "B." (Look in early Analog mags, IIRC for some info about these, if interested.)

 

-Larry

 

I also found this short description, although this is not the article I was thinking of (mid-way down the page):

http://www.atariarchives.org/creativeatari/Questions_and_Answers.php

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So if you didn't use DD, then the Doubler (type) code should work? The only fly in the ointment is that there may be a code check in the Doubler to detect whether someone has the additional ram of the Doubler. If someone had "pulled its teeth" or wrote similar code, then that sounds like the device this thread is describing.

 

 

As a matter of fact, it does. I once pulled the code apart and assembled it to work with a different ram config. Also to see the special format command and add it to another 1050 hardware upgrade that I had.

Looking tonight at my Harddrive images I have, the source files are damaged. DOHHHHHHHHH!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

James

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Hi,

 

thanks for all suggestions. But it´s not US Doubler (this one needs extra RAM). It was really only a new firmware, no need to solder or replace any other than the PROM/EPROM (ok, you´ve to change the zero ohm resistors to select EPROM usage, if the 1050 has a PROM on it).

 

Perhaps this one never circulated outside germany. A lot of people I have knew have use it in the mid eighties to get a little more speed, the Speedy 1050 wasn´t on the market and the Happy 1050 to much expensive and hard to get. When the Happy clones comes for cheap, this solution was not more needed any longer.

 

It would be very interesting historically to find if anyone still has this (slightly) modified 1050 ROM to dump and analyze.

 

A similar effort was done by users groups on the 810 to improve the original really slow skew that the format routine used by modifying the sector order in the ROM, and it was still 10% faster than Atari's updated 810 ROM that later came out in September or October 1981. That 'faster' format skew became known as the "Chicago format", which was also adopted as the default format skew by the 810 Archiver, 810 Happy, 1050 US Doubler, and many others. Based on the articles in scanned users groups newsletters, I was able to re-create this modified 810 firmware by patching it myself.

 

http://atariage.com/forums/topic/279363-the-atari-810-revision-b-rom-has-finally-been-found-dumped/?p=4113840

 

I suspect they patched the stock 1050 firmware to use the same "Chicago format" skew. If the skew was exactly the same as the "Chicago format" - it would indicate the authors had seen disks or firmware from the other mods. If it's slightly different, they may have invented it from scratch on their own.

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I remember, BITD when I was working on a full disk demo (which never saw the light of day), my loader did this in software, i.e. it read the sectors in a different order for a slight speed up.

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If you have the ICD mod and SpartaDOS, you can read the sector sequence on a one track pass and then read the sectors in a fast order on the rest of the disk. You take advantage of the high speed SIO even though the disk is the low speed format.

 

I wrote something that did this a long time ago... in a galaxy far, far away.

 

Bob

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If you have the ICD mod and SpartaDOS, you can read the sector sequence on a one track pass and then read the sectors in a fast order on the rest of the disk. You take advantage of the high speed SIO even though the disk is the low speed format.

There are two programs I know of that can read 'standard skew' formatted disks at Ultraspeed with a US Doubler:

 

- CopyMate 4.4 ( https://archive.org/details/a8b_Copymate_v4.4_1987_Palmer_Mike_Hillery_R._US) - It will automatically try reading sectors in three different orders until the fastest is found. The first two try to read 'Standard' skew or 'Chicago' skew at UltraSpeed. Lastly it falls back to reading sequentially which is fastest if the disk was actually formatted with an ultraspeed skew, or if reading a standard skew disk on a stock 1050, or other drive incapable of UltraSpeed.

 

- SCOPY included with at least SpartaDOS Construction Set 2.3/3.2 ( http://seriouscomputerist.atariverse.com/pages/dos/dos.sparta.htm) - By default, it will assume the disk is in standard skew, and will read the sectors out of order for maximum speed on a US Doubler in ultraspeed. If you know the disk is formatted with Ultraspeed, you have to manually specify the /u command line switch to tell it to read sequentially. Neither way reads a disk formatted with Atari 810 Revision B any quicker. (That was a pretty small use case by 1985 though heh)

 

My main interest here though, is formatting disks with the fastest skew for use at standard 1X SIO speed. The 810 "Chicago" ROM, 1050 US Doubler, 810 Archiver, 810 Happy create disks with this skew, which is about 10% faster than disks formatted by Atari's 810 Revision C, and stock 1050. It would be neat to see if the modified 1050 ROM tf_hh remembers uses the exact same skew or not.

 

It be interesting to create a new variation of the Stock 1050 Revision "L" and WST ROM's that formats with the "Chicago" skew for 1X SIO. I can probably try to do this, but would need assistance calculating the correct checksum.

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