Jump to content

Photo

The TRAK track buffer?


32 replies to this topic

#1 Larry OFFLINE  

Larry

    River Patroller

  • 3,962 posts
  • Location:U.S. -- Midwest

Posted Mon Jan 23, 2017 6:24 AM

Now there's a "blast from the past" that usually doesn't get much discussion here (and also apparently didn't sell many drives)...

 

I've seen several threads here that describe the "memory tricks" used to store sector data for R/W.  And those remind me of another one -- the TRAK with its track buffer.  (I had an AT-D2 that worked, and think I still have the board from one.)  IIRC, it had a 2K memory module for the track buffer.  No problem in SD, but on the surface, it is a bit shy of enough to hold the full track's data in the buffer, so it must have held at least one sector's data somewhere else in the system. (?) 

 

Anyone have any ideas about how that might have been done?

 

-Larry



#2 evilmoo OFFLINE  

evilmoo

    Chopper Commander

  • 139 posts

Posted Mon Jan 23, 2017 6:58 AM

According to this: http://www.strotmann..._AT/TRAK-AT.pdf

The 4K (not 2K as you remember) printer buffer was also used as a sector cache.  It could also be upgrated to 16K.

 

The text also implies it behaved more as a sector cache than a track cache, since it mentions non-contiguous disk areas.  Theoretically it could be smart enough to recognize a sequential read sequence, and cache accordingly.  That would require some firmware analysis though. :)



#3 Larry OFFLINE  

Larry

    River Patroller

  • Topic Starter
  • 3,962 posts
  • Location:U.S. -- Midwest

Posted Mon Jan 23, 2017 7:54 AM

Brain freeze... Yes, you are right,  had to be 4K if upgraded to do the Turbo mode & DD -- 4096 bytes, but a full DD track is 256 * 18 = 4608 bytes, so still not enough room.  My TRAK certainly appeared to read a full track at a time.  As I recall, you had to run either a utility to open the sector cache or run a modified Dos that did the same thing.  It has been at least 20 years since I had it.  Don't believe I ever used the printer feature. But I did have the utility disks.  Had really big pcb's in it, and I believe a daughter board that plugged into the main board.

 

Here is an article from Antic that also mentions the 2K buffer that could be upgraded to 4K, so there could have been a change along the way to upgrade the models to 4K (as the docs you linked indicated).

 

http://www.atarimaga...rivesurvey.html

 

It would be cool if someone else who had used the TRAK could weigh in on it, also.

 

-Larry



#4 kheller2 OFFLINE  

kheller2

    Stargunner

  • 1,131 posts
  • Location:PA, USA

Posted Wed Jun 13, 2018 8:49 PM

I just obtained one of these drives: AT-D2 with some slave drives but haven’t gotten to test it yet. I was curious if anyone has the procedure for upgrading it to 16k and if it really does track buffering. Supposedly according to its literature you needed a turbo ROM upgrade to do that and software. Sounds a bit suspicious.

#5 JR> OFFLINE  

JR>

    Chopper Commander

  • 223 posts

Posted Fri Jun 15, 2018 12:39 PM

I just obtained one of these drives: AT-D2 with some slave drives but haven’t gotten to test it yet. I was curious if anyone has the procedure for upgrading it to 16k and if it really does track buffering. Supposedly according to its literature you needed a turbo ROM upgrade to do that and software. Sounds a bit suspicious.

This post reminded me that I had a TRAK drive sitting in its box out in my garage.

 

Might just be a simple plug and play.  The 2x2k SRAMS are 24 pin, but are in 28 pin sockets.  A ROM upgrade might be required as well.

Attached Thumbnails

  • 20180615_1127471.jpg


#6 Nezgar OFFLINE  

Nezgar

    Dragonstomper

  • 756 posts
  • Location:Regina SK Canada

Posted Fri Jun 15, 2018 12:42 PM

Do you have the means to dump the 4KB 2732A EPROM?

#7 JR> OFFLINE  

JR>

    Chopper Commander

  • 223 posts

Posted Fri Jun 15, 2018 12:44 PM

Do you have the means to dump the 4KB 2732A EPROM?

Yes If I can revive the old PC my Burner is plugged in to.  It's been on my to do list for a while :)



#8 JR> OFFLINE  

JR>

    Chopper Commander

  • 223 posts

Posted Fri Jun 15, 2018 2:14 PM

Yes If I can revive the old PC my Burner is plugged in to.  It's been on my to do list for a while :)

It's alive....IT'S ALIVE!   Actually all I had to do was move the monitor cable from the Crazy Dots card in the TT030 to the PC....sigh!

 

It's been a really long time since I've booted a Windows 98 machine!

 

Here's the rom:

Attached Files



#9 kheller2 OFFLINE  

kheller2

    Stargunner

  • 1,131 posts
  • Location:PA, USA

Posted Fri Jun 15, 2018 2:22 PM

 I toasted the darn hard ribbon cable to the front panel when opening it.  That was brittle.  Gotta dig out the soldering iron one night.  Boo.  please dump that ROM because mine is not that version (pic enclosed)

 

On the other hand, this is just a standard early PC floppy mech: Teac FD-55A-00-U.  Should be able to hook up a second one to the outside connection, instead of using one of the Trak "proprietary" slave drives.

 

 

 

IMG_4007.jpg



#10 Nezgar OFFLINE  

Nezgar

    Dragonstomper

  • 756 posts
  • Location:Regina SK Canada

Posted Fri Jun 15, 2018 2:59 PM

Sure is nice and compact for a drive that can control 3 more external ones!

#11 JR> OFFLINE  

JR>

    Chopper Commander

  • 223 posts

Posted Fri Jun 15, 2018 3:28 PM

Apparently there is still some missing software to activate the turbo mode on these.  Even with the 'Turbo' rom, it's just running at normal 1x speed.

 

The manual does mention their "Turbo-Charged" software diskette that can be purchased from your dealer.

 

"This software includes utilities that enable your drive to access information from your diskette many times faster than any other drive available today"



#12 kheller2 OFFLINE  

kheller2

    Stargunner

  • 1,131 posts
  • Location:PA, USA

Posted Fri Jun 15, 2018 4:04 PM

The way the manual is worded, it makes it sound like you only need the 4K buffer and software to have track buffering.  It then implies how wonderful it is if you had the 16K upgrade where an entire program could be stored in the print buffer.

 

Does anyone have the first set of disks that has the DDINIT and diagnostic software?  Does anyone have any TRAK disks?  I haven't found any yet, but I've just started searching.



#13 JR> OFFLINE  

JR>

    Chopper Commander

  • 223 posts

Posted Fri Jun 15, 2018 5:05 PM

It may be running with a track buffer.  Honestly it's probably been 30+ years since I've used a stock 810 or 1050, so I may be forgetting how slow they actually are.  It's only running 1x SIO speed though.



#14 JR> OFFLINE  

JR>

    Chopper Commander

  • 223 posts

Posted Fri Jun 15, 2018 5:35 PM

Ooooooo! MrMartian apparently worked some of his magic into a replacement rom for the TRAK!
 


#15 JR> OFFLINE  

JR>

    Chopper Commander

  • 223 posts

Posted Mon Jun 18, 2018 5:06 PM

The good news - The TRAK dirve using the Trubo 1.13 does seem to have an active track buffer with 4K Ram. (with no additional TRAK software.)

The bad news - It appears to ONLY work with single density disks formatted with a normal sector skew.

The worse news - It's actually slower with the track buffer than without!

I was running some speed comparisons on several disk drives to see how they compare and to see if and how well the track buffers on them work with different densities and sector skews and SIO drivers.  When I started testing the TRAK drive, something odd happened.  When reading from the drive, it would spin up, but then there would be a long pause before any data was actually read.  After the pause the data for a complete track came through pretty quickly, then this would repeat for every track being read.  At first I though it was having problems reading the disk, but it had no problem reading the same disk with a different firmware.  So I ran a test that read just one track.  The first time a track is read, the drive spins up, pauses for a while, then reads quickly.  On subsequent reads of the same track, the drive still spins up for some reason, but there is no pause, before the data is read, again quickly as if coming from the buffer.  Unfortunately the lack of data transfer while the buffer is being filled makes the whole process slower than reading the same number of tracks without a buffer, except when a single track is read multiple times!   This only occurs with a single density disk formatted with the normal sector skew.  Double density disk and single density disks formatted with a USD skew do not exhibit this behavior and do not appear to be doing track buffering at all.

On a more positive note.  The same drive using MrMartian's US Doubler ROM seems to make the drive act like a USD 1050, and actually outperforms my homebrew USDouble drive on USD skewed Double density disks by about 25% (I double checked this test).

Here's the raw data.  The times are the number of seconds to read 100 sectors from each disk.  Timing was done by hand.  The Stock OS Tests had no high speed drivers loaded, and the other tests were using Hias's 13. patch.

Attached Thumbnails

  • Speed tests.jpg

Edited by JR>, Mon Jun 18, 2018 5:09 PM.


#16 Nezgar OFFLINE  

Nezgar

    Dragonstomper

  • 756 posts
  • Location:Regina SK Canada

Posted Mon Jun 18, 2018 6:32 PM

Interesting! First thought - did you format the disks for testing in the drive before testing? Maybe it's native format has a slightly different skew to work optimally? Interesting the USD ROM is faster than the 1050 USD. Maybe from faster cpu reducing latency. I guess both USD's would format the same ultraspeed skew since the sector order is provided by the computer..

#17 kheller2 OFFLINE  

kheller2

    Stargunner

  • 1,131 posts
  • Location:PA, USA

Posted Mon Jun 18, 2018 6:35 PM

I should get you the TRAK 1.11 ROM out of my drive and have you see what the times are.  And, someone needs to get you a 1050 Duplicator drive using a WST mech.  SPEED.

 

And I must be reading the chart incorrectly.  Why would a 1050 USD drive at USD skew be SLOWER than a stock SD skew?



#18 JR> OFFLINE  

JR>

    Chopper Commander

  • 223 posts

Posted Mon Jun 18, 2018 7:07 PM

Interesting! First thought - did you format the disks for testing in the drive before testing? Maybe it's native format has a slightly different skew to work optimally? Interesting the USD ROM is faster than the 1050 USD. Maybe from faster cpu reducing latency. I guess both USD's would format the same ultraspeed skew since the sector order is provided by the computer..

I used the same 4 disks for all tests.  They were all formatted on the USD 1050.  I used Spartados X 4.49 to get the USD skew.

 

I should get you the TRAK 1.11 ROM out of my drive and have you see what the times are.  And, someone needs to get you a 1050 Duplicator drive using a WST mech.  SPEED.

 

And I must be reading the chart incorrectly.  Why would a 1050 USD drive at USD skew be SLOWER than a stock SD skew?

 

Without high speed drivers the USD 1050 was slower with USD skew. Not sure why.  May have to revisit that.

 

For comparison, running the same setup with RespeQT and Pokey 0 via SIO2PC are.

 

Stock OS

sd - 16

dd -  29

 

Hias

sd- 3

dd- 6



#19 Nezgar OFFLINE  

Nezgar

    Dragonstomper

  • 756 posts
  • Location:Regina SK Canada

Posted Mon Jun 18, 2018 7:08 PM

A USD skew formatted disk in a drive with no track buffer at 1x sio speed will miss the next sectors on the same revolution and have to wait until the next revolution to catch them.

#20 Nezgar OFFLINE  

Nezgar

    Dragonstomper

  • 756 posts
  • Location:Regina SK Canada

Posted Mon Jun 18, 2018 7:12 PM

I'm curious to see the sector skew the various trak ROMs lay down during format. Do you have a drive capable of showing the sector skew? Ie happy with archiver/chip emulator, or speedy disk mapper.

The 'normal' skew might be slightly different between drives. Ie the trak turbo might need to use disks it formatted itself.

#21 JR> OFFLINE  

JR>

    Chopper Commander

  • 223 posts

Posted Mon Jun 18, 2018 7:20 PM

I'm curious to see the sector skew the various trak ROMs lay down during format. Do you have a drive capable of showing the sector skew? Ie happy with archiver/chip emulator, or speedy disk mapper.

The 'normal' skew might be slightly different between drives. Ie the trak turbo might need to use disks it formatted itself.

 

Unfortunately I've been unable to get the TRAK to fomat a disk with any firmware so far. It lays down the format, tries to write a sector, tries to read it (based on panel lights), and then just stops dead. I have to power cycle it to bring it back. 



#22 AtariGeezer ONLINE  

AtariGeezer

    River Patroller

  • 2,665 posts
  • Location:Santee, CA

Posted Mon Jun 18, 2018 7:48 PM

 

Unfortunately I've been unable to get the TRAK to fomat a disk with any firmware so far. It lays down the format, tries to write a sector, tries to read it (based on panel lights), and then just stops dead. I have to power cycle it to bring it back. 

It could be a bad FDC,  I had the same problem with my ATR-8000 as it read fine, but failed formatting/writing...



#23 evilmoo OFFLINE  

evilmoo

    Chopper Commander

  • 139 posts

Posted Mon Jun 18, 2018 8:08 PM

I seem to remember Trak's default double density sector skew was awful.



#24 JR> OFFLINE  

JR>

    Chopper Commander

  • 223 posts

Posted Mon Jun 18, 2018 8:16 PM

It could be a bad FDC,  I had the same problem with my ATR-8000 as it read fine, but failed formatting/writing...

 

Thanks, I'll have to check it out.  Seems to be an epidemic actually.  Out of all those drives, The USD 1050 was the only one that would complete a format.



#25 Nezgar OFFLINE  

Nezgar

    Dragonstomper

  • 756 posts
  • Location:Regina SK Canada

Posted Mon Jun 18, 2018 8:31 PM

Ah.. Keep in mind the default 'normal speed' sector skew from a USDoubler is a little faster than the standard 9:1 in single density compared to a regular 810, 1050. (more like 8:1) Could be enough to trip up the trak ROM buffer optimizations if it's assuming sectors should be in a particular order...




0 user(s) are browsing this forum

0 members, 0 guests, 0 anonymous users