XF551 vs. 1050 disk compatibility

[graywest]

Hello all,

 

I've owned Atari computers for a long time, but always used them with 1050 drives. Recently, I purchased a lot of Atari floppies containing random games and files from Ebay, tried to boot them on my 1050 drive, and none of them seem to work.

 

I noticed a handwritten label on one of the disks that says "DISK = XF551" so I assume they were originally created with an XF551 drive.

 

Am I correct in understanding that disks formatted with an XF551 are not backwards compatible with the 1050 drive?

 

Wanted to figure out if it's my incompatible drive, or just a batch of bad disks. Thanks for the help!

Edited July 26, 2020 by graywest
added a little more information

[bfollowell]

The XF551 was a double-sided, double-density drive capable of storing up to 360KB on compatible diskettes. The stock 1050 was a single-sided, enhanced-density drive, which most people didn't use. Most people used it as a single-density drive or upgraded the hardware to fully support double-density. If the disks are single-sided, single-density, the should work. If they're single-sided, double-density, they could work, assuming your drive has the US Doubler or Happy or something like that installed. If they were full DS, DD disks, they will never work with your 1050.

 

[graywest]

11 minutes ago, bfollowell said:

The XF551 was a double-sided, double-density drive capable of storing up to 360KB on compatible diskettes. The stock 1050 was a single-sided, enhanced-density drive, which most people didn't use. Most people used it as a single-density drive or upgraded the hardware to fully support double-density. If the disks are single-sided, single-density, the should work. If they're single-sided, double-density, they could work, assuming your drive has the US Doubler or Happy or something like that installed. If they were full DS, DD disks, they will never work with your 1050.

 

Much appreciated! My 1050s are stock, no upgrades that I know of. So I'm thinking it's the latter - someone has created these disks with an XF551, and they're never going to be compatible with my current drives.

 

Sounds like it's time for me to upgrade!

[bfollowell]

XF551s show up for sale on eBay. Not nearly as often as 1050s, but routinely, in the states anyway.

[tjlazer]

2 hours ago, graywest said:

Am I correct in understanding that disks formatted with an XF551 are not backwards compatible with the 1050 drive?

Correct, if it was formatted on the XF551 it would be a double sided 360k format.  And that will not work on the 1050.

[BillC]

If you have a PC with a 5-1/4" drive it may be possible to create ATRs of these floppies, then access them via emulator.

 

Edited July 26, 2020 by BillC

[+Larry]

Yes, having an XF551 is useful, if you can find one at a decent price.  Another option is Charles Marslett's ATUTIL which is a PC (Dos) utility for reading/writing Atari DD disks.  Having the disks formatted on an XF551 is a big help, since it uses the timing hole for formatting.

http://wordmark.org/mydos.html

 

I don't know about using ATUTIL with DS/DD (if that is how they are formatted).  BITD, I only used it with SS/DD.  If you can read the disks on a PC, you would still need a way to get them back to the Atari -- an SIO2PC device with APE (and maybe RespeQt).

 

A big question is whether there is stuff on those disks that you really want (or can you find it on the web?), and how many disks you need to "decrypt."

 

-Larry 

[graywest]

7 hours ago, Larry said:

Yes, having an XF551 is useful, if you can find one at a decent price.  Another option is Charles Marslett's ATUTIL which is a PC (Dos) utility for reading/writing Atari DD disks.  Having the disks formatted on an XF551 is a big help, since it uses the timing hole for formatting.

http://wordmark.org/mydos.html

 

I don't know about using ATUTIL with DS/DD (if that is how they are formatted).  BITD, I only used it with SS/DD.  If you can read the disks on a PC, you would still need a way to get them back to the Atari -- an SIO2PC device with APE (and maybe RespeQt).

 

A big question is whether there is stuff on those disks that you really want (or can you find it on the web?), and how many disks you need to "decrypt."

 

-Larry 

Thanks! I do have an SIO2PC device, but no 5 1/4" floppy for my PC.

 

I'm thinking about getting an XF551 if I can find one at a reasonable price. There may not be anything on the disks that is worth saving, but I like to look for games that may not be archived anywhere, weird and unusual files, homemade software that people wrote a long time ago, and that sort of thing. It's like a treasure hunt for me. ?

[+Nezgar]

How many disks are you looking at archiving? If you can't find a drive and it's not too many, maybe you can send the disks to someone with an XF551 to try to archive them to ATR files for you.

 

Also, XF DSDD disks are formatted in a way that upgrading a 1050 with a US Doubler would allow you to read at least the first half of a double sided disk.

[graywest]

54 minutes ago, Nezgar said:

How many disks are you looking at archiving? If you can't find a drive and it's not too many, maybe you can send the disks to someone with an XF551 to try to archive them to ATR files for you.

 

Also, XF DSDD disks are formatted in a way that upgrading a 1050 with a US Doubler would allow you to read at least the first half of a double sided disk.

Thanks! It's about 50 disks, so probably more than anyone else would be willing do help out with in their spare time.

 

Are XF551 drives particularly rare? I'd like to pick one up. I see quite a few 1050s on Ebay, but no XF551s.

[cwilbar]

XF551 drives show up periodically on eBay.  They come with sticker shock however.  They are also prone to certain problems related to the power jack, power switch, regulators, etc.  Atari must have decided to use ape spit to hold the copper foil onto the PCB.... as it doesn't work worth shit :-).  Very sensitive PCBs...

 

The cheaper ones will be untested drives (most of what is up on eBay are untested (or at least claim to be untested)).  However, you'll want to have some basic soldering and troubleshooting skills.

 

I may have one extra working drive available, but its mighty hard to part with XF551s :-). 

 

If your 1050 is stock and you have enough electronic skills, you should think about the US Doubler upgrade.  It consists of a replacement ROM and you have to make a piggyback of a pair of 6810 RAM chips (as RAM needs to be doubled for double denstity operation).  I have a number of 1050s to finish going through and repairing, and think I may update some of them to US Doubler before 're-homing' them to new owners.

 

 

[graywest]

16 minutes ago, cwilbar said:

XF551 drives show up periodically on eBay.  They come with sticker shock however.  They are also prone to certain problems related to the power jack, power switch, regulators, etc.  Atari must have decided to use ape spit to hold the copper foil onto the PCB.... as it doesn't work worth shit :-).  Very sensitive PCBs...

 

The cheaper ones will be untested drives (most of what is up on eBay are untested (or at least claim to be untested)).  However, you'll want to have some basic soldering and troubleshooting skills.

 

I may have one extra working drive available, but its mighty hard to part with XF551s :-). 

 

If your 1050 is stock and you have enough electronic skills, you should think about the US Doubler upgrade.  It consists of a replacement ROM and you have to make a piggyback of a pair of 6810 RAM chips (as RAM needs to be doubled for double denstity operation).  I have a number of 1050s to finish going through and repairing, and think I may update some of them to US Doubler before 're-homing' them to new owners.

 

 

Thanks for the info. So the US Doubler in a 1050 will allow me to read all data on a disk written with an XF551?

 

I have basic electronics and soldering skills, never piggybacked RAM before though. From a brief search on the internet, I think I could PROBABLY do that. Would be a fun project to try, anyway.

 

If you find that you do have a spare working XF551, shoot me a PM and let me know how much it might take to persuade you to part with it. ?

[BillC]

15 minutes ago, graywest said:

Thanks for the info. So the US Doubler in a 1050 will allow me to read all data on a disk written with an XF551?

A DD modified 1050 will only be able to access side 1 of a an XF551 formatted DSDD disk, not side 2.

[manterola]

Another option (only if like playing with soldering iron) is to build a xf551 clone. The minimum you need is a 360KB floppy drive you can get for less than $40 if you wait enough, the Dropcheck Xf551 board (or sf551 board) and all the components to build the board (and a power supply and one SIO cable). It is a very interesting project. Even to make it more fun and save some money on shipping you can order almost everything times two, and build both a 5.25" clone and a 3.5" clone.

In general, the more complicated (for me) part is to get a proper case for the board and mechanisms (you can use a 1050 case as some members of this forum have done before).

I am not sure you will save some money, but it is certainly a nice project if you consider this a hobby.

Just my $0.02

  

[cwilbar]

On 7/27/2020 at 3:39 PM, graywest said:

Thanks for the info. So the US Doubler in a 1050 will allow me to read all data on a disk written with an XF551?

 

I have basic electronics and soldering skills, never piggybacked RAM before though. From a brief search on the internet, I think I could PROBABLY do that. Would be a fun project to try, anyway.

 

If you find that you do have a spare working XF551, shoot me a PM and let me know how much it might take to persuade you to part with it. ?

As already mentioned, USD will add true double density support to the 1050, but it will not make it dual sided.  The XF551 is double sided as well as double density.

 

 

[djglish]

You could also look for an Indus GT drive or a Rana 1000 drive.  I believe they are both double density/double sided.

My first drive was a Rana 100o and it worked great.  I saw one on ebay for about $40.00.  It does say DD but not sure if it was double sided.

Here is the link

https://www.ebay.com/itm/Atari-Rana-1000-SD-ED-DD-Disk-Drive-with-Disks-Power-Supply-Cable-and-Manual/203068800752?hash=item2f47d7fef0:g:BJwAAOSwoPdfK3uM

 

[bfollowell]

28 minutes ago, djglish said:

You could also look for an Indus GT drive or a Rana 1000 drive.  I believe they are both double density/double sided.

My first drive was a Rana 100o and it worked great.  I saw one on ebay for about $40.00.  It does say DD but not sure if it was double sided.

Here is the link

https://www.ebay.com/itm/Atari-Rana-1000-SD-ED-DD-Disk-Drive-with-Disks-Power-Supply-Cable-and-Manual/203068800752?hash=item2f47d7fef0:g:BJwAAOSwoPdfK3uM

 

 

This is not correct in either case. Both the Indus GT and the Rana 1000 were both single-sided, double-density drives.

 

[djglish]

Thanks for the correction

[bfollowell]

11 minutes ago, djglish said:

Thanks for the correction

I'm not 100% certain, but the XF551 may have been the only DS/DD drive for the 8-bits. It was definitely the only one from Atari. There was the 1053, but it vaporware, or prototype at best.

 

Is anyone aware of another DS/DD, 360KB drive for the 8-bit line? Did any of the 3rd party manufacturers make one?

 

Edited August 9, 2020 by bfollowell

[+davidcalgary29]

46 minutes ago, bfollowell said:

I'm not 100% certain, but the XF551 may have been the only DS/DD drive for the 8-bits. It was definitely the only one from Atari. There was the 1053, but it vaporware, or prototype at best.

 

Is anyone aware of another DS/DD, 360KB drive for the 8-bit line? Did any of the 3rd party manufacturers make one?

 

Yes, there were quite a few released both for North American and central European markets.  Trak, Percom, Astra, LDW,(?) Toms, and others released DS/DD drives, although I've never seen any of them in the wild. No, wait -- I think I saw a Trak AT-D4 for sale ONCE on eBay in about twenty years of watching. The max capacity of the XF551 was still 360K per disk with a double-sided diskette, although that was obviously increased with those 3.5" mods.

[manterola]

I have a couple of Panasonic 360KB mechs that I'd love to use to build xf-551 clones. I tested them with my existing original xf-551 board and they work great. 

The problem is finding a suitable and not that expensive 5.25" case...but someday I hope I'll do this project. 

 

 

[cwilbar]

One solution to an enclosure when building a drive, is an old SCSI external tape drive or SCSI cdrom drive.  A long time ago these were common and plentiful both in 5.25 FH (full height), and 5.25 HH (half height).

 

I am using an old Andatco open face drive enclosure for a 5.25" FH SCSI hard drive to house a 5.25" 360K floppy drive and a 1.44M 3.5" floppy drive for use with my Supercard Pro.  For some reason this one already had the SCSI cabling stripped out of it (hence choosing it since I wouldn't need that stuff).

 

There is an improved XF551 PCB out there (Atari's AF551 PCBs were the product of significant cost cutting, and if you stare at them cross eyed the traces will leap off of the PCB ? ).

There is also a board called an SF551 which is intended for putting in an Atari ST 3.5" external drive enclosure turning into an 'XE' style 3.5" disk drive.  It is the XF551 circuitry in a different format PCB.