DualStor Tips and Techniques

This is a compendium of tricks, tips, and techniques for using Dualstor that I have gathered from the IBMOBI forum on Compuserve, from other users, and from my own experience. They are presented in no particular order. It is by no means complete but it is a good place to start and may give you some ideas. If all else fails, including asking questions on Compuserve IBMOBI forum section 2, call 1-800-426-7299 and ask for Dualstor support. If they tell you that they have never heard of Dualstor or that it is published by Microsoft or other such garbage, ask for a supervisor. Also ask for a supervisor if they try to charge you for service. If this happens make sure that they know that this is an Options by IBM product. IBM policy prohibits you from asking for Don Nagy, the one person there who really DOES know Dualstor, so please don't do that. I am also willing to help if you are willing to be patient with me. If you want help or have a tip or suggestion that you think should be added to this file please let me know. I can be reached at pofc@ix.netcom.com or on Compuserve at 72730,1006

I make the assumption all through this document that you have good hardware; in other words that your tape head is clean, you have a good, properly formatted or preformatted tape, no wiring problems, etc.

Read the readme file that comes with Dualstor. It contains a wealth of information!

If possible at all try to format your tapes under DOS. It is certainly possible to format a tape under OS/2. I have done it many times, but it is not the best way to go. QIC-80 is a 'standard' that was developed a long time ago for DOS machines. It is cheap and unreliable even on the DOS platform. The key word there is 'cheap'. Lempel-Ziv error correction gets around the 'unreliable' pretty well. The real problem we run into on multitasking systems (NT is not exempt; it has more problems than OS/2 WRT QIC-80) is that it is very timing sensitive. If a pre-emptive MT systems grabs a few clock cycles away from the tape program at the wrong time (during a write) the data is going to end up in the wrong place. If that happens during a format the tape, or at least that block, will be unusable. The moral of the story is always format under plain DOS. --- Always bulk erase your tape before trying to format it. Before DS version 3.0 this was a requirement. So far as I'm concerned it still is. You cannot get a good format on a previously used tape without bulk erasing it. This isn't opinion; it's Gospel. --- Before beginning, run chkdsk from a floppy boot against all of the drives that you will be backing up to ensure that there are no errors. --- If the QIC-80 file system gives you problems, try using the Dualstor filing system instead. Even if the QIC-80 file system doesn't give problems use the Dualstor system. Its a better system. Only use the QIC-80 file system on tapes that you will be using to transport data to other machines.

--- The IROPT commands and other parameters mentioned here usually don't work from the command line and you'll waste a lot of time trying. They need to be placed in Config.sys and you will need to reboot each time you change one. Sorry but that's the way it is.

They look like: DEVICE=C:\DUALSTOR\IP22DRV.SYS iropt=Y

--- There should be an option to shorten the BUS-ON time in the setup of the later versions of the Adaptec controllers. Consult your manual to determine how to change this parameter. --- DISABLE any EXTERNAL cache. (AMI BIOS offers this option under Advanced) --- Use a "cheapo" IDE controller for your floppy interface. --- There are switches that can be used in some cases to customize DualStor. You are supposed to be able to tell DualStor to set certain switches when you invoke it from a command line by putting the /j after the DS command. It doesn't seem to be working correctly, but you can just type SET (variable)=(parameter) at the command prompt before starting DS. You can also add them to your CONFIG.SYS so they are initialized at IPL time. The switches are the same for DS v1.06 and 2.0.(and 3.0 also)

Here are some of the parameters that can be used in the Config.sys file with DEVICE=C:\DUALSTOR\IP22DRV.SYS iropt=????. THEY ARE CASE SENSITIVE.

D = PC/AT class machines with floppy controllers having a FIFO buffer use Demand mode DMA transfers. Both the Intel 82072 and 82077 chips fall into this class. Irwin 4100 Tape Controller board uses an Intel 82077 chip. d = Standard single byte DMA transfer mode - regardless of the floppy controller type.

Demand mode decreases the part of the bus bandwidth consumed by the tape read/write transfers.

X = One megabit transfers ARE allowed

x = One megabit transfers ARE NOT allowed.

By default 1 megabit transfers are allowed. If 1 megabit transfers overload the system bus, then the "x" option may need to be used. -

DualStor's auto config normally determines which mode to use so most people do NOT need to use these.

--- The Insider controller is similar in form and function to an Irwin 4100 tape controller. Both act as "secondary" floppy controllers and provide 1M bps backup speeds.

The DS software has a special "hook" to allow it to work with the Irwin 4100 card. If you place the following line in your OS/2 CONFIG.SYS file, it will recognize the 4100 card at a non-standard address: SET 4100=P:300,I:5,D:1 In the above case, my port address is 300h, the IRQ is 5, and the DMA channel is 1. I don't know if your Insider controller is close enough to masquerade as a 4100, but you might try the above, just to see. --- Try removing the floppy driver, IBM1FLPY.ADD,from your Config.sys.

DualStor may want to talk to the hardware card directly, and if the card is already managed by another driver, DS may not be allowed direct access.

--- Here are some variables you might try in Config.sys: SAMPLE        SET (variable)=(parameter) --

VARIABLES

- IRDRV - - IRSRCH - is the case insensitive variable, that tells the tape software WHERE to FIND the tape drive.

The tape driver uses a default drive searching sequence to test for the presence of a tape drive. This default sequence may be replaced with a user configured sequence - using IRDRV or IRSRCH variables. This may be useful in situations where the software erroneously detects a drive, or where multiple drives are supported. Example below... EXAMPLE : IRSRCH=SYSFDC:3,4100:2 In the example above, the instruction is to look for a tape drive at unit select 3 on the system floppy controller, and unit select 2 on an IRWIN 4100 PC/AT bus tape controller.

The EQUIVALENT command using IRDRV is per the example below... EXAMPLE : IRDRV=04,43   or     IRDRV=4,43 In the example above, IRDRV uses a 2 digit number to specify a controller and the low-order of unit select. If the high-order digit is missing, 0 (system floppy controller) is ssumed.


 * NOTE** The unit select used by IRDRV is in the range of 1-4 while the unit select for IRSRCH is from 0-3

SUPPORTED controllers with the IRDRV and IRSRCH variables: IRSRCH        IRDRV Name          High Digit      Controller --     -- SYSFDC         0               System floppy ALTFDC        1               Alternate floppy 4100MC        2               Irwin 4100 Micro Channel 4100MCB       3               Second Irwin 4100 Micro Channel 4100          4               Irwin 4100 PC/AT Bus 4100B         5               Second Irwin 4100 PC/AT Bus

VARIABLES (continued) Certain variables may be set to specify tape controller specific parameters. For example: EXAMPLE : 4100=P:370,I:6,D:2,T:2,T:0
 * SYSFDC -
 * ALTFDC - With the Irwin 4100 and 4100B Controller for the PC/AT Bus machine

The line above specifies that an Irwin 4100 PC/AT controller is installed and configured with a base I/O port address (P) 0370hex, using IRQ (I) 6, DMA channel (D) 2, and has two tape units (T), with one wired for physical unit select number 2, and the other is 0. The general for for controller parameter specifications is as follows in the example below: = :=  := :  * = SYSFDC   --  System Floppy controller ALTFDC  --  Alternate controller 4100    --  Irwin 4100 PC/AT bus controller 4100B   --  Second Irwin 4100 PC/AT bus controller *       P        --  Base port address in hex I       --  Interrupt ReQuest line  (IRQ) D       --  DMA channel T       --  Tape unit number  (valid=0-3) B       --  FIFO threshold [0-FFFF]

--- If you have been unable to get satisfactory performance with DualStor, the Adaptec bus-mastering controllers and the CMS Jumbo 250 try these tips:

(1) Set the bus speed to 8 mHz. My Ami BIOS had a setting of SYNCHRO for its bus speed. When I turned this off I was able to set my bus to 8. I have a DX2 80, so my cpu bus is a 40. I set it to divide by 5. If I had a DX/2 66 I would have set it to divide by 4, etc.

(2) On the line that loads the Dualstor device driver in CONFIG.SYS, add IROPT=dx.

Previously I had turned off my external cache, but I have it back on now. I get streaming on backups and restores with up to 4 meg/min speeds. I get better performance on Stackered FAT volumes than on my one HPFS volume. --- add this to your config.sys SUPRESSPOPUPS=C It writes the error messages to your C drive.

Issue command HELP SUPRESSPOPUPS for more info! --- If, during an attempt at a stand-alone restore, you experience an error during boot-up (such as hanging on the 'Minicartridge tape driver. Version x.xx' message), edit the config.sys on the SR disk #2 using a text editor and move the DualStor 'DEVICE=x:\x\IP22DRV.SYS' and 'RUN=x:\x\IP2XDMN.EXE' statements to the top of the config.sys and re-boot your system as a possible solution.

--- If Dualstor decides that it doesn't like a tape that you know is good (tape not formatted message or some such) then take that tape out and put in another tape, any other tape. Let it cycle the tape back and forth until it stops and then put the first tape (the one it didn't like) back in and only _THEN_ hit 'OK' on the popup window. Nine times out of ten it will read the tape fine on the second try.

SHOE-SHINING PROBLEMS
If you have a high-speed floppy controller capable of handling a 2.88M floppy drive then you should be able to get 7-10 M/min backup speeds but many times the drive will shoe-shine excessively. First try setting wait states in your CMOS to 0 (or less than what they are now) and if you still have shoe-shining try playing with the variable:

sysfdc=b:x - where x can be set to 1,2 or 4-10hex. The default is 3.

This changes the FIFO threshold.

With my new BL 100 Motherboard I set all waits to 0 and use DEVICE=E:\DUALSTOR\IP22DRV.SYS sysfdc=b:8 and I now get backup speeds of 9-12 M/min where with the default settings the shoe-shining was so severe that I had to disable high-speed transfer with iropt=x --- Try using level 1 compression rather than level 2. --- Run Benchmark tests after each change on a known directory of at least 50M of both zip and text files. I know this is time consuming but it will pay off in the long run.

STANDALONE RESTORE PROBLEMS
Be sure of a few things BEFORE you have a system crash and really NEED to use the SR procedure. Test everything. Use your best tape for the system backup and rubber-band the three diskettes to the tape box and put them in the safe. After testing them of course.

--- Be sure that your system is configured in CMOS to boot from A: and then C:. If it's the other way around you can't boot from the floppy unless your HD is really shot. --- Be sure that when you upgrade your system you remake your master tape and a new set of SR floppies. It is much easier to do it then than trying to rewrite the config.sys on your SR disk #2 using TEDIT in order to take something like a new SCSI card into account. I speak from sad experience. --- If you are repartitioning your drive remember that you will have to format any bootable DOS C: drives with a floppy and the command FORMAT C: /S to transfer the system files before running SR. Dualstor will happily write the boot files on there but they won't be in the right place and they won't work. --- If you run FDISK and repartition then think things through! Do it on paper first. Read the online docs about FDISK and print them out and keep them with the tape and disks. --- Do the same thing with the docs on FORMAT. Just in case you didn't, the command is FORMAT D: /FS:HPFS /L for an HPFS drive and FORMAT D: /FS:FAT for an FAT drive. You will need to know the label of the disk so run DIR /P first. --- When you are ready to do the restoration of the system put the tape in the drive and type SR. It will read the tape, find a backup set, and ask if you want to restore it. You can only restore complete sets and only to a drive formatted the way the original was. You can't restore an FAT backup set to an HPFS drive with the SR disks. You can, of course, do this with Dualstor PM.