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kheller2

DOS 3 history?

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If you want cp/a I am sure I can upload it again, I bleed the off ancient relic from time to time.... I still use the variety of these DOS as witnessed by the disks and atr's I have talked of and uploaded should one have taken notice.... DOS.s were primarily written by one person or another but a group of persons of some sort was always involved...

Edited by _The Doctor__

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Dos 3 was actually much better than most people said. As stated correctly, Dos 3 is essentially FAT. Not only is file management much simpler, also random access into files is much simpler, POINT and NOTE is fully canonical, and its pure FMS part requires less memory due to a simpler structure, and it is more modular than Dos 2 due to its separation into FMS, KCP and KCPOVER.

 

It was unfortunately simply too late in the market to compete with the popular Dos 2 design, and due to the rather small sector size of the 1050 (Atari going cheap again with only 256 bytes of RAM in the drive) it had to merge 8 sectors into one cluster, which was wasteful. With 256 byte sectors - as the competitors had - clusters would have to be 2 sectors long, hence half the size (o one quarter of the number of sectors) which would have been much more reasonable.

 

One can also say that Dos 3 came too early, as it would have worked better with more capable hardware, or came with the wrong hardware, as the 1050 was not offering any competative storage capacity.

 

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My impression was the two bugged releases killed DOS 3, it spread like wild fire what the problems were and never really recovered or lost the stigma... it should have re released as 3.1 but the DOS 3 stickers were bought and paid for :(

Edited by _The Doctor__

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_The Doctor__ do you actually have a working CP/A+ ? The oldest OS/A+ I've seen was 1.20, which seems to be a bit odd... I do know that there WAS a version of CP/A+ for the Apple computers which had a ported Atari FMS...but I've yet to see that weird little unicorn, although it did actually exist....

 

-Thom

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Did anyone ever figure out how to modify DOS 3 to support larger disks? It _has_ to be possible, with as much modularity that was baked into the FMS.

 

-Thom

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I have a bootable cp/a work disk around here somewhere... it's got whatever we were playing with on it... I'll look tonight... are we sure I didn't already post it here somewhere?

Edited by _The Doctor__

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Use this on an 800 some project or another is on it...

CPADISK2.ATR

 

also there were (4) DOS 3 versions out there... two were buggy and one was fixed up... and the final internal version.... theories of large disk use are not entirely off base ;)

Edited by _The Doctor__

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Okay I took a look at it and it was a work in progress disk 'Influencing others for MTR' 1982 and is indeed on OSS CP/A boot disk with 7 IOCB'S.

Since it's not about DOS 3 if I find more of it, I will put it in the Roklan thread

Edited by _The Doctor__

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I remember getting DOS 3 with my 1050 in 1986 and my long time Atari owning friend telling me not to touch it and stick with 2.5. I eventually wiped over the disk so I could use it for something else. Being a 16 year old with little money a "free" 5 1/4 disc was more than enough justification.

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Use this on an 800 some project or another is on it...

attachicon.gifCPADISK2.ATR

 

also there were (4) DOS 3 versions out there... two were buggy and one was fixed up... and the final internal version.... theories of large disk use are not entirely off base ;)

 

I'm so very disappointed that all four version have not been archived. So so sad. :grin:

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3 of the 4 are everywhere thats the problem :), it would be best if only the final pack in and the engineering versions were all that was circulating. In fact the only one missing is engineering final... some people thought the fixed retail was the engineering version but it is not....

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How do we tell the difference between versions? I have a number of original DOS 3 disks and would like to put them on on Atarimania but I can't tell which versions they are.

 

Allan

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How do we tell the difference between versions? I have a number of original DOS 3 disks and would like to put them on on Atarimania but I can't tell which versions they are.

 

Allan

 

Supposedly this way:

To determine if you have an early version, boot your copy of ATARI DOS 3 with ATARI BASIC, and execute the following command from ATARI BASIC:

PRINT PEEK (1816)

 

If the value returned is '53', your copy of ATARI DOS 3 is a current version and does not require modification.

 

If the value returned is '51' or '56', please contact ATARI Customer Relations at one of the toll free numbers or address listed below, to obtain a program which will update ATARI DOS 3 to the current revision level."

 

That implies 53,51,56 and the unknown working 4th version.

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? PEEK (1816)

53 is fixed version

51 or 56 are the buggy versions

 

Engineering should be other values as it progressed

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oh my we're doing it again see post

http://atariage.com/forums/topic/102915-dos-3-history/?p=1250065

Kheller2 covered that part of it a while ago

 

Yeah I need to get that white card scanned and up to Atarimania.

 

So what is that internal version of DOS3 that Curt is talking about... seems to be something that wasn't even similar to the released DOS3.

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It worked on the development system as well as retail units that system had access to larger drives and other hardware some of which was thought would not be needed at that time for the consumer... however time reveals the consumer wanted what developers needed :)

Edited by _The Doctor__
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It was unfortunately simply too late in the market to compete with the popular Dos 2 design, and due to the rather small sector size of the 1050 (Atari going cheap again with only 256 bytes of RAM in the drive) it had to merge 8 sectors into one cluster, which was wasteful. With 256 byte sectors - as the competitors had - clusters would have to be 2 sectors long, hence half the size (o one quarter of the number of sectors) which would have been much more reasonable.

But with 256 bytes per sector in MFM your disk would have 720 physical sectors, not 520. And 720 sectors cannot be covered with 256 clusters, 2 sectors each.

 

This was the main limitation of DOS 3 and DOS 4: these both were FAT-based, but it was FAT-8. Unless there is a method of extending the cluster address to more bits (which I am not aware of), every DOS 3 and DOS 4 installation is stuck at max. 256 clusters per disk in DD and max. 128 clusters per disk in SD/ED. This is why DOS 3 uses 8 sectors per cluster: 8*128*128 = 131072, which, provided that some areas of the diskette are used for system purposes (FAT, directory, boot region, such stuff) covers the entire possible data area for an ED floppy. And nothing more.

 

DOS 4 for the same reason is even more wasteful, it uses 1,5k clusters in DD (six 256-byte sectors per cluster) to cover a 360k disk.

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This thread got me thinking about Dos 3, so I looked through my archives. I have had at least two brand new boxed 1050's, and they both came with Dos 3. Both disks are "bad" with a PEEK(1816) value of 56. The ATR at Atarimania is "good" with a value of 53, but it also has a bunch of non-dos files on that image. My Dos 3 errata sheet also mentions the PEEK(1816) values and indicates that owners with values other than 53 should contact customer support for a program that will patch the system file. Anyone have that program or know anything more about how it worked? A simple one-for-one byte replacement or?

 

-Larry

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This thread got me thinking about Dos 3, so I looked through my archives. I have had at least two brand new boxed 1050's, and they both came with Dos 3. Both disks are "bad" with a PEEK(1816) value of 56. The ATR at Atarimania is "good" with a value of 53, but it also has a bunch of non-dos files on that image. My Dos 3 errata sheet also mentions the PEEK(1816) values and indicates that owners with values other than 53 should contact customer support for a program that will patch the system file. Anyone have that program or know anything more about how it worked? A simple one-for-one byte replacement or?

 

-Larry

I found an original '53' version that is un-notch. I am copying it now and will replace the other one on Atarimania in a few minutes.

 

Allan

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