Beebs and SCSI Hard disks.....

[IBM portable PC]

With about 1500 reads, this thread is in the top 5 topics. We really should finalize some procedures here.........

BASIC code to alter drive configurations would appear to be a priority, then we can all focus on which drives work etc whilst I really want to move forward on my project to use a PC running MS/PC with an ISA SCSI card running in Target mode I.e. The Beeb will think the PC's 256 byte sector RAMdrive is a Winchester whilst this virtual Winchester may be loaded and saved (thus easily shared by etc!) from the PC's drives.

[BeebMaster]

I'm going to start backing up my floppy discs by imaging them on my PC very soon.

I'm about to trial the new method I've devised which I think will fulfil my criteria, viz:

1. Allow me to play about with Beebs whilst doing it
2. Not use Windows
3. Take less than 1 hr per disc

The plan is to backup a floppy disc to CF drive, using some suitable method like *BACKUP (if it will take it on) or ADT's *SECTORS or OSWORD&72 and then put the CF card in the PC and use that script I have for throwing away 256 of every 512 bytes so that you essentially get an ADFS disc image as a file.

Stage 2, when I get it working, will be to image an ADFS floppy in 1 pass using the ARM7 and store many disc images on the CF drive as files. When I've got the disc image on the PC, I can use that ADFS Fuse thing to pull out the individual images files from the disc image. This would also enable to me to image DFS discs by storing them as an image file on the ADFS CF drive.

I can't do stage 2 at the minute because I'm having problems with using ADFS 1.53 with the ARM7 (but not ADFS 1.33, though I can't use 1.33 to access the floppy interface so that doesn't really help unless I do everything on a BBC B, which may be a possibility). I will start a thread about ADFS 1.53 and the ARM7 eventually.

Anyway, that all was a prelude to saying that backing up my floppy discs (particularly the ones with my own software on) is now the BeebMaster top priority and the first discs I will be doing are my Winchester/SCSI/SCSI-2 formatter/utilities discs.

[jgharston]

I can't do stage 2 at the minute because I'm having problems with using ADFS 1.53 with the ARM7 (but not ADFS 1.33)

Well, if you're trying to use ADFS 1.53 on the BBC, you *will* be having problems, ADFS 1.53 is for the Master (and works fine with 6502/Z80/ARM CoPro), as you have discovered you need ADFS 1.33 for the BBC.

DiskToImg will create ADFS disk images on the BBC/Master.
*DiskToImg 4 :0.filename -size 640K -v or
CHAIN "DiskToImg 4 :0.filename -size 640K -v"
will image the 640K ADFS disk in drive 4 (floppy drive 0) and store it in a file called filename on drive 0 (hard drive 0).

[BeebMaster]

Well, if you're trying to use ADFS 1.53 on the BBC, you *will* be having problems, ADFS 1.53 is for the Master (and works fine with 6502/Z80/ARM CoPro), as you have discovered you need ADFS 1.33 for the BBC.

No, it was definitely with a Master (actually with my "Master AIV" specifically when I discovered the problems, although the same problem happens on Station 1 as well). I found I could use ADFS 1.33 as a workaround (but not access the floppy drives) on a Master. I'd remembered that ADFS 1.30 works on a Master, my souped-up Master ET came with that version of ADFS, so I thought I'd try ADFS 1.33 and it helped. More on all that on a nearby thread coming soon, once I've collected my thoughts/findings.

[IBM portable PC]

For those that want to get into SASI/SCSI but don't have a Beeb to SASI (SCSI-1) interface board, you may like to try and build one!

At this site http://www.adsb.co.uk/bbc/winchester/ you will find documentation, including a schematic diagram, for what was known as the Tubby SASI board.

Clem

[IBM portable PC]

...................... backing up my floppy discs (particularly the ones with my own software on) is now the BeebMaster top priority and the first discs I will be doing are my Winchester/SCSI/SCSI-2 formatter/utilities discs.

This really is excellent news Thank you

[BeebMaster]

Well, here we go then...for what it's worth!

Warning first though - a lot of the stuff on these discs is either work in progress, or abandoned projects that I couldn't get to work or didn't have time to pursue, or utilities written to suit my own personal convenience or situation, or code I deliberately wrote to be unstructured and inefficient and against all rules of good programming, just because I decided on that day that that's how I would write it (!!!!)....

And before trying anything, always LOAD and LIST it first, as a lot of my utils start doing their work without any user input, including formatting, writing and otherwise completely destroying data!!

RAR contains images of 3 ADFS floppies -
WinchForms - Winchester Disc formatters and various Adaptec and Xebec ST506 type Winchester utilities
SCSI2Utils - utils for using SCSI-2 discs, including formatter, verifier and Change Definition routines etc.
UltraForm - formatter for Adaptec ACB4000 & ACB4070 controllers, heavily based on "Superform" but with many enhancements, including the ability to cope with discs with more than 128 defects, better bad sector address translation, select MFM or RLL controller, and separate options to verify and initialise discs.

There aren't any filename extensions to the three images, but I think they conform to .adf format, that is, they are a sector dump of an ADFS "L" floppy disc from sector &0 to sector &9FF in numerical order.

22iii2014.rar

(176.5 KiB) Downloaded 132 times

[IBM portable PC]

Well, here we go then...for what it's worth!

Warning first though - a lot of the stuff on these discs is either work in progress, or abandoned projects that I couldn't get to work or didn't have time to pursue, or utilities written to suit my own personal convenience or situation, or code I deliberately wrote to be unstructured and inefficient and against all rules of good programming, just because I decided on that day that that's how I would write it (!!!!)....

And before trying anything, always LOAD and LIST it first, as a lot of my utils start doing their work without any user input, including formatting, writing and otherwise completely destroying data!!

RAR contains images of 3 ADFS floppies -
WinchForms - Winchester Disc formatters and various Adaptec and Xebec ST506 type Winchester utilities
SCSI2Utils - utils for using SCSI-2 discs, including formatter, verifier and Change Definition routines etc.
UltraForm - formatter for Adaptec ACB4000 & ACB4070 controllers, heavily based on "Superform" but with many enhancements, including the ability to cope with discs with more than 128 defects, better bad sector address translation, select MFM or RLL controller, and separate options to verify and initialise discs.

There aren't any filename extensions to the three images, but I think they conform to .adf format, that is, they are a sector dump of an ADFS "L" floppy disc from sector &0 to sector &9FF in numerical order.

22iii2014.rar

Can someone now zip and upload some of their spare time, that's the crucial component I appear to be missing in my quest to get SCSI working on my Beeb..........

[BeebMaster]

Tell your boss that you're going down to 4 days a week on the same pay, then enjoy your 3-day Beeb weekend every week, like I do!

[IBM portable PC]

Okay, I've finally had a chance to play around with a PC as a SCSI Target device i.e. a virtual hard drive.

Look at:

https://www.google.com/webhp?sourceid=c ... 2&safe=off

and you will easily find 8xxtarg.zip which contains the sample code that was released by Symbios Logic in the 90's. You may also like to download some product manuals for suitable Symbios Logic SCSI controller chips.

After setting up a PC with an appropriate Symbios Logic PCI based SCSI controller and ASPI driver, you simply run the 8xxtarg.exe. It asks for various options and then the PC appears on the SCSI bus as a hard drive. The simulated drive is in RAM on the PC and can be saved and loaded. I'm using a HP Omnibook 800CT sub notebook running PCDOS 7 (only) which has a suitable SCSI chip on the motherboard.

Symbios Logic supplied full source code in c and so we now 'simply' need someone to make the required change/s to support 256 byte sectors as currently only; 512, 1024, 2048 and 4096 are supported.

Needless to say, this will not be difficult. I know one or two developers who may be able to assist, however I'm sure that one or two users here can also.

8xxtarg.exe appears quite stable, from another vintage PC I've been able to happily FDISK and FORMAT /S to my hearts contents and can also verify that the saving and loading of the virtual drive works well also which is going to be a great feature for backing up Filestors etc or for uploading or emailing images.

[IBM portable PC]

Aug 26 update: I have now been able to successfully FDISK, FORMAT C: /S and boot PCDOS from the SCSI Target simulated drive. Of course thus is useless for a Beeb, however it proves that SCSI Target mode can work as we require. I am also speaking to someone who has dabbled in C today ref adding:
1. 256 Byte Sector support
2. Parity on/off menu item
3. SCSI 1/SASI - SCSI 2 menu item
4. Drive size beyond 65MB

[IBM portable PC]

Here's a little more......

Few SCSI adaptors appear to have supported SCSI Target mode, however Symbios Logic had several SCSI controller chips that did:

"The SYM53C7XX/8XX/10XX family of chips run on target as well as host devices. Target operation is very similar to host operation, except that the SCRIPTS processor responds to SCSI commands from the host rather than initiating the commands. " Symbios® SCSI SCRIPTSTM Processors Programming Guide Version 2.2 page 11-1

Unfortunately 53C7XX onward do not support an ISA bus I.e. We have to use a new fangled PCI bus machine as the virtual drive.

I am confident that with 256 byte support that we will soon have an excellent SCSI solution for the Beeb.

I can also now report that I have been able to repeatedly boot my Tandy 1000 XT clone with PCDOS 7 from the Pentium 166 Hosts Target 65MB RAM based simulated drive.

[dangardner]

Great work on this, thank you. I'm looking forward to experimenting with SCSI target mode again once I unpack all my Beeb stuff following my house move.

Few SCSI adaptors appear to have supported SCSI Target mode, however Symbios Logic had several SCSI controller chips that did:

There are also several (most? all?) of the much more widely available Adaptec chips which are supposed to work with SCSI target mode and are supported by the FreeBSD scsi_target driver but I couldn't get any of them to work. However, in my recent house move I discovered a box with a bunch more PCI SCSI cards, including a few more Adaptecs and a Symbios 53CXXX so I'll be trying to get this working either with your DOS solution with the Symbios card or using FreeBSD with the Adaptecs.

I don't think anybody has mentioned this yet but you can download the Borland C++ compiler free of charge at http://forms.embarcadero.com/forms/BCC3 ... erDownload. I haven't tried it with the 8xxtarg.zip source but the README states that it was written using Borland C++ 4.5.

[IBM portable PC]

Here is another 256 Byte Sector solution and it includes the ability to disable parity!

http://shop.codesrc.com/index.php?route ... duct_id=50

However, again how would we create a backup or share an 'image' of the 256 Byte Sector virtual drive it will simulate?

I'll stay with SCSI Target Mode, for now...........

[IBM portable PC]

Here are a few manuals relating to Symbios SCSI, including SCSI Target Mode:

http://www.cebix.net/downloads/bebox/53c810a.pdf

http://www.causeuse.org/hauke/macbsd/sy ... xpg_21.pdf

http://www.tenox.net/docs/scsi/the_prog ... sawert.pdf

http://bitsavers.informatik.uni-stuttga ... _Nov92.pdf

http://bitsavers.informatik.uni-stuttga ... /ncr/scsi/

[IBM portable PC]

I'm a virgin to c, however I have now taken a look at the source included with 8xxtarg.zip and even I can see the block size variable. I've only spent 10 minutes on this, however I suspect that allowing 256 (and perhaps 128 and 64 [I believe some vintage systems went down to 64) byte sectors may be simpler than I thought. It's 'simply' sending data to Target SCSI Host, on which the 'drive' is 100% in RAM and so we're not writing 256 byte sectors directly to the hosts drive etc. 8xxtarg.exe then saves the data in RAM as a file and I suspect that it doesn't care whether the block size variable was; 4096, 2048, 1024, 512 or for that matter 256,128 or 64.

I overlooked the fact that the 'drive' size is simply limited by the amount of RAM on the host system. I can live with the 64MB on my HP Omnibook 800CT for now, most SASI systems had only 5,7,12 or perhaps 20MB drives attached and of course this includes the Beeb.

The SCSI Parity Enable/Disable option will require a little thought whilst ensuring compatibility with SASI/SCSI1 may best be achieved by 'simply' ensuring that no SCSI-2 commands are used and of course this may not be a trivial exercise.

This will have to wait now until I receive my Borland C++ CD from Amazon (it includes PDF's of all manuals i.e. iPad food) for about $20.

[johnkenyon]

The SCSI Parity Enable/Disable option will require a little thought whilst ensuring compatibility with SASI/SCSI1 may best be achieved by 'simply' ensuring that no SCSI-2 commands are used and of course this may not be a trivial exercise.

Shirley if the Beeb is acting as an initiator, it will only send SCSI-1/SASI commands, so there is no need to ensure that SCSI-2 commands aren't used.

The only requirement is that any responses from the target should be "SCSI-1 like", which is almost certain to anyway happen in response to a SCSI-1 command.

[IBM portable PC]

I've finally managed to obtain a Akhter 1MHz -> SASI (SCSI-1) bridge board and an Adaptec ACB-4XXX controller board from eBay, item number 291232912749 and it wasn't cheap!

http://www.ebay.co.uk/itm/291232912749? ... 26_rdc%3D1

These are the remains of a Technomatic Drive which includes the original Rodime Winchester (hard) drive which I don't want so make me an offer!

[george.h]

If you are tempted to try plugging a slightly more modern SCSI drive like the Seagate Hawk 1GB type directly into the Akhter board, be aware of the issue it has with shorting out 0V and +5V on the SCSI connector through the drive.

I'll have to check precisely which pin it is when I get home but BeebMaster has came across the self same issue. You need to cut the track leading to this pin to be sure of not needing BeebMaster's Fire Engine (TM).

[johnkenyon]

If you are tempted to try plugging a slightly more modern SCSI drive like the Seagate Hawk 1GB type directly into the Akhter board, be aware of the issue it has with shorting out 0V and +5V on the SCSI connector through the drive.

I'll have to check precisely which pin it is when I get home but BeebMaster has came across the self same issue. You need to cut the track leading to this pin to be sure of not needing BeebMaster's Fire Engine (TM).

Pin 34 is the one.

SCSI docs say GND (http://pinouts.ru/HD/ScsiInternal_pinout.shtml)
Original Acorn host adaptor says +5v (http://stardot.org.uk/mirrors/www.bbcdo ... dapter.gif)
AIV SCSI adaptor says "SPARE" and terminates it (http://stardot.org.uk/mirrors/www.bbcdo ... daptor.png)

[george.h]

Pin 34 is the one.

That's the sod! LOL....

The drive I "discovered" that little quirk on is the one on the left in my Avatar pic.... That isn't what killed it but it still has the scorch marks by the IDC connector where it vaporised the track leading to that pin....

[BeebMaster]

Yes, cut pin 34 on the SCSI cable!!!

Otherwise it will MELT!

This was a problem even in the 1980s - my Digistore tape drive has a hole drilled through the track for pin 34 on its Acorn host adapter board!!

[BeebMaster]

If you are tempted to try plugging a slightly more modern SCSI drive like the Seagate Hawk 1GB type directly into the Akhter board, be aware of the issue it has with shorting out 0V and +5V on the SCSI connector through the drive.

That sort of drive will definitely work, I've got about 6 ST32550N drives formatted to 512MB ADFS and they work a treat.

With pin 34 cut on the SCSI cable.

And the operating definition changed to SCSI-1.

And the right jumper settings for parity and terminator power etc.

[george.h]

That sort of drive will definitely work, I've got about 6 ST32550N drives formatted to 512MB ADFS and they work a treat.

With pin 34 cut on the SCSI cable.

And the operating definition changed to SCSI-1.

And the right jumper settings for parity and terminator power etc.

Yep we've had this conversation a while back, though I never changed the SCSI definition, but had to change the behaviour of Request Sense after a reset.

[BeebMaster]

That sort of drive will definitely work, I've got about 6 ST32550N drives formatted to 512MB ADFS and they work a treat.

With pin 34 cut on the SCSI cable.

And the operating definition changed to SCSI-1.

And the right jumper settings for parity and terminator power etc.

:lol: Yep we've had this conversation a while back, though I never changed the SCSI definition, but had to change the behaviour of Request Sense after a reset.

That's right, it's an alternative way of getting the drive to come to life. Especially as you can't do the change definition on a Beeb because the drive isn't recognised by the Beeb at that point to send the command to it!

[george.h]

That's right, it's an alternative way of getting the drive to come to life. Especially as you can't do the change definition on a Beeb because the drive isn't recognised by the Beeb at that point to send the command to it!

It is not quite as simple as the Beeb not recognising it. I'll have to research whether using Change Definition to set the drive in SCSI I mode alters the default behaviour after a reset to acheive the same effect.

Anyway the problem I found is when entering *ADFS (or *FADFS then trying to access the drive) the Beeb would just hang. I found that by default the Seagate Hawk drive logs a Check Condition status after a reset (incuding power-on) which can only be cleared by sending a Sense Request command. Until it is sent a Sense Request command it ignores everything sent to it completely, not even issuing any response. What I found is that the Beeb is happily trying to send commands to it, but none of them are Request Sense so the drive ignores them and stays silent. Meanwhile the Beeb is waiting for the response to the commands it has sent, which never comes. Changing the behaviour of the drive after reset to log the Check Condition but NOT require a Resuest Sense solved the problem - and it stayed in SCSI II.

I'll think I'll add another project to my list of "things to do" - writing a SCSI Tool utility (ROM would be great) that doesn't use ADFS. When I altered the behaviour of my drive is was by directly controlling the SCSI bus - I didn't use the ADFS SCSI subsystem (forgot it had one and didn't know how to use it!).

P.S. The drive on the left of my Avatar pic is a Seagate Hawk 1GB SCSI drive with it's lid off. This was one of a pair used on the first file server I looked after - a Netware 3.11 server with duplexed 1GB drives (duplex=mirrored, i.e. RAID 1, but with dual controllers so each drive is on a seperate SCSI controller) - for Oki. The other is attached to my Master!

[IBM portable PC]

I'm still pursuing SCSI target, however here's another option. An MFM ST-506 drive emulator!

http://www.pdp8.net/mfm/mfm.shtml

What I really like about this option, is that we don't have to discard the Xebec/Adaptec SASI controllers which are of course known to work with the Beeb.

I'm ordering a board for my newly acquired Technomatic which contains the coveted Adaptec controller.

It appears that our 256 byte sector woes will soon be a consigned to the history books once and for all.

[george.h]

I'm still pursuing SCSI target, however here's another option. An MFM ST-506 drive emulator!

http://www.pdp8.net/mfm/mfm.shtml

What I really like about this option, is that we don't have to discard the Xebec/Adaptec SASI controllers which are of course known to work with the Beeb.

I'm ordering a board for my newly acquired Technomatic which contains the coveted Adaptec controller.

It appears that our 256 byte sector woes will soon be a consigned to the history books once and for all.

A very interesting approach, especially as you'll be preserving more of the "orginal BITD" hardware. I look forward to reading how you get on!

[george.h]

Apologies for bumping a (very) old topic, but could you do another image of your BBC SCSI tools please BeebMaster?

I tried downloading the disk image archive you did (22iii2014.rar) but can't get the resultant disk images to read in BeebEm - my first port of call before transferring them to floppy via my DataCentre...

Pretty please!!!!!!

[BeebMaster]

I discovered a while back that the method I'd been using to image ADFS floppies (basically using ADT's *SECTORS command on an ARM7 co-processor to do the whole disc in one pass and then a *SAVE of the data read into RAM) wasn't working, only the first few tracks had actually been copied. I don't know how it happened because on most of the floppy discs where the last sector on the disc was in the map as free I put an end of disc marker in the last four bytes ("END"+&0D) so I could check that I was reading the right number of bytes, and all the checks I did showed that the last sector had been read into RAM and written back to the CF drive I was using for the images.

I suppose what might have been happening could have been that it was reading a block of sectors and writing them, but not doing that individual operation fully, but by the time it got to the last block of sectors up to the end of the disc, it just happened that the final block of sectors was small enough for all the data to be being read/written correctly in that final operation.

Anyway, the short answer is yes I will, but it will involve a new image being made, probably with a bit of BASIC to do it with OSWORD &72, which I will do as soon as I can.