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Adaptec ACB-2070A RLL 8bit ISA low level setup with Seagate ST-277R-1

Robin4

Veteran Member
Joined
Sep 25, 2011
Messages
501
Hi all,

Found some time to go further with my Retro PCs.
Locally i found and bought an Adaptec ACB-2070A (later revision which mentioned in the manual which i found on the internet) for just 15 euros. So i took the gamble.
Seller said it was an MFM and RLL controller.. But i found more on the RLL side in the manual. So iam guessing its just maybe rll only.

Before i bought it, i checked the manual to see if the supported drives matched with the one i wanted to use. Iam iam guessing it would? or not?

My problem here is to setup the controller, so it would work with my ST-277R-1 drive. For now its more a test to see if i can get the controller board in a working state.

Normally there are much better controllers to find that are very easy to install and setup.. Just go with Debug and knowing the rom address.
Iam not high skilled with using Debug.. But if i can find the right commands, then its not hard to doing the rest.


The situation is that right now iam only having an ms-dos 6.22 bootdisk with Debug on it..

The way the controller is configurated is due tables like it seems.. In the manual there a decent long list of hard drives.

About the tables. i found it more clearer then want the manual is listed.

https://stason.org/TULARC/pc/hard-di...ACB-2070A.html



If iam correct there are only 4 tables listed? If i have to match.. The controller is setup as table 0 [MN and OP] right now are connected.
Iam guessing i need table 2?

But strange it wouldnt match correctly 1:1 on the table specs of my hard drive.. Those are: 820 cyl, 6Heads, 26 sec / track.

The table of the controller saying (as listed on stason.org)

981 cyl , 5 heads (and nothing about the sec/track.)

how do i setup it right so i can low-level format it and getting the controller board working.



How can i find the rom address to go with the low-level formatter utility.? Normally its set on the PCB.. So then you could find it.

But this controller card seems how have an hardware fixed rom address??
 
Debug address seems to be: -G=C800:CCC

Found it on the last page of the manual.. Thought it was only listed for ST-238 drive.

It asks now for Sector Interleave. (iam guessing 3, like the ST-238. But iam really not sure about it.) And i think i just could ignore the jumper settings for drive 0? (just leave it on ST-238 drive) (there is no way to disable this)
 
Easy answer! You must first LL format the drive before using it (DEBUG and then G=C800:CCC per the manual). The formatting routine will ask if you want to use the default jumper-selected drive geometry. If you say "N", then it prompts for drive geometry data, formats the drive and saves the geometry info on disk. The next time the system is booted, the controller loads that geometry information instead of using the default jumper info.

For an 8-bit XT-class controller, 3:1 interleave should be adequate.
 
Do you maybe know the Step pulse rate of the drive?? From 0 to 7.. I took a gamble on 3 but iam now sure..

Its formatting now, but drive seems to bit slow for what it is.

You i know i need LL format the drive.. But didnt know how the enter that low-level format utility, and also didnt know that standard tables setting on the PCB had anything to do with my drive.

Iam only not sure if all settings i had to put in, in the low level formatter where the correct values.
 
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Pretty much any drive from the ST412 on uses buffered seek, so the step rate isn't critical. Basically the "step rate 3" on the Adaptec controller fires out step pulses every 13 microseconds. You would only want to do something different if (1) you were using a very old drive with unbuffered seek or (2) the drive required setup pulses coming at a much slower rate. Note that this has no real effect on the actual time it takes to move the head carriage.
 
Is there anything i could do for a performance test, and see if the drive could be more optimized.

I cant remember that this ST-277R-1 was this slow and doesnt making that really loving RLL head movement sound. (what my other drive does) (drive acts to brave now)

always can re-low format drive again if it need to..

But no i can see that the controller card i purchased is in working state.

Do you maybe know the basic setting for step pulse rate for this drive? ( how do i need to see this (low is slower and higher is faster?)


Its now Verifying Format in Logical unit 0.
 
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Ok. Thanks for all your help Chuck..I know enough for this moment.

Stupid thing is i found that step pulse rate in the manual.

They say:

Seek step pulse rates.

0 3.0 milli seconds
1 Reserved (dont know why?)
2 30 micro seconds.
3 13 micro seconds.
4 200 micro seconds.
5 70 micro seconds.
6 Reserved
7 Reserved


In an older manual of ST 251 where also ST 277R is in:

The step periode must be between 3 usec and 200 usec.

Maybe going to try 4 and see what it would do.
 
What kind of machine is this being used it? There is an issue with 8-bit cards used in 16-bit 286/386/486 systems - they somehow become slower and require a higher interleave value. The 8-bit RLLs cards I am familiar with have an optimal interleave of 4 on 8088 base system.

Just run spinrite and find out what the optimal interleave should be. If you don't want to run through the extensive testing and rewriting, just stop after it tells you the interleave and re-LLF using that value.
 
What kind of machine is this being used it? There is an issue with 8-bit cards used in 16-bit 286/386/486 systems - they somehow become slower and require a higher interleave value. The 8-bit RLLs cards I am familiar with have an optimal interleave of 4 on 8088 base system.

Just run spinrite and find out what the optimal interleave should be. If you don't want to run through the extensive testing and rewriting, just stop after it tells you the interleave and re-LLF using that value.


This drive and controller setup is going to be installed in an Laser XT/3 8086 10 Mhz machine.. But currently i've put it in my working 8088 class XT V20 machine on 8 Mhz.. This was only to get the controller and card running.
 
2 days ago i tried spinrite version 1.1. Its saying 3 was the optimal setting.. So i left it on that.
 
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