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Thread: SCSI-to-SD Instructions?

  1. #1
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    Default SCSI-to-SD Instructions?

    I apologize if this has been asked in the past.

    Is there a set of step-by-step instructions posted anywhere for how to interface an SCSI-to-SD adapter onto a PDP-11 system? I have a very small PDP-11/23 system with an Emulex SCSI interface, currently interfaced to a small SCSI hard disk and an SCSI Zip drive. I'd like to add on an SCSI-to-SD adapter, get it running, and then make it to be my primary SCSI drive and eliminate the current SCSI hard disk.

    I'm not very good at reading between the lines, so I would greatly appreciate a hand-holding step-by-step set of instructions.

    Thanks very much, in advance, for your patience and advice (or pointers).

    smp

  2. #2

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    smp --

    This is the setup I used for my H11. I will look around and see if I took any notes during the process, but IIRC it was pretty easy to do from on-line info only. I created an emulated RD54 (which is 172MB?) to run RT11. The SCSI2SD connects to your PC by USB for configuration and setup. I have it mounted in a 3D printed case I bought on-line.

    http://www.vcfed.org/forum/showthrea...07-and-SCSI2SD is where I talked about the process a bit.

    Rich

  3. #3

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    I haven't done it in awhile, but I remember it's quite simple. Hardest part is getting into the code on the Emulex to create the new drive. It's defined how to do
    this in the UC manuals. I can look it up, but it should be on Bitsavers. What Emulex? I have a UC17.

  4. #4

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    Hi smp,

    I have a page with some notes about how to use a SCSI2SD with a QBUS PDP-11. My page doesn't really deal with the physical interface or the configuration of the SCSI2SD board, but it does include notes about how to move RT11 images between SIMH and the SCSI2SD environment. Not sure if this will help much, but here's the link -> http://avitech.com.au/?page_id=2735

    Malcolm

  5. #5
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    Default

    Thanks very much, guys. I appreciate all your pointers and info.

    Quote Originally Posted by tradde View Post
    I haven't done it in awhile, but I remember it's quite simple. Hardest part is getting into the code on the Emulex to create the new drive. It's defined how to do
    this in the UC manuals. I can look it up, but it should be on Bitsavers. What Emulex? I have a UC17.
    I have a UC07 in my tiny system. I have the manual and used the internal firmware to format my original Macintosh SCSI HD that I'm using now.

    Looks like I need to dive in, and just use the setup software to partition 4 devices and give them SCSI addresses. Then I can add it into my system and again use the UC07 firmware to find the new devices and format them. After that, I can copy over my boot SCSI disk contents to one of the devices, and reset the SCSI address to be 0. Then, maybe I can boot from it?

    Sounds easy enough. I guess I'll have to find out...

    smp

  6. #6
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    Default

    Quote Originally Posted by Mal View Post
    Hi smp,

    I have a page with some notes about how to use a SCSI2SD with a QBUS PDP-11. My page doesn't really deal with the physical interface or the configuration of the SCSI2SD board, but it does include notes about how to move RT11 images between SIMH and the SCSI2SD environment. Not sure if this will help much, but here's the link -> http://avitech.com.au/?page_id=2735

    Malcolm
    Hi Mal,

    Thanks very much for the pointer. I notice that you have used pretty large sizes for your SCSI devices. So far for me, I've never been able to get the UC07 to create a disk image any larger than 32MB. Of course, that's been fine for me as I never even get close to filling that up. I see that you've created much larger disk sizes - does RT-11 recognize them to be those sizes?

    Thanks!

    smp

  7. #7
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    Default

    OK!

    I took the plunge, and I purchased a version 5.1 SCSI2SD board:

    https://www.ebay.com/itm/SCSI2SD-v5-...53.m2749.l2649

    While waiting for it to arrive, I downloaded the SCSI2SD-UTIL application program. The board came today, and I was quickly able to set up four SCSI devices on the SD card. I set them to be device 1, 2, 3, & 4, so they would appear in between my existing boot HD (0) and my Zip drive (5).

    I attached the new interface onto my ribbon cable, and I booted into the EMULEX setup firmware. The auto-setup command is truly a blessing! All the devices were found, and I programmed them into the Emulex NOVRAM. Re-booting the PDP-11, I was able to INI DU1: through DU4: and then I copied all the files from my boot HD onto DU1:. For safety, I also did a COPY/BOOT on the RT11XM.SYS file. I also copied all the files from my Zip drive onto DU2:. I powered down, removed the original boot HD and the Zip drive from the chain, reset the SCSI IDs on the SCSI2SD board to be 0, 1, 2, & 3, and performed another auto-setup on the Emulex interface.

    This was moment of truth, so I powered down and attempted to boot with only the SCSI2SD board attached. Yes! Success! I now have my PDP-11/23 operating from a modern SCSI2SD board, with four SCSI disks available.

    I can't say how long I have agonized over going ahead and attempting this. Way too long. Thanks very much fo you folks you offered your advice and support. I'll now save my SCSI hardware away, hopefully to never need it again. A bit of space cleared on my table to populate with something else, I'm sure.

    I'm psyched. This has been a great experiment for me!

    smp

  8. #8
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    Default

    The only downside I have found using SCSI2SD vs (in my case) Seagate 2.1G SCSI drives is raw data transfer. SCSI2SD is async only and on my Emulex UC17 it appears to top out at somewhere about 600KB/sec. Using the Seagate drives I get just north of 2MB/sec. Running 2.11BSD I do notice it to be slightly less responsive on my 11/44 with the SCSI2SD vs Seagate drives, when it comes to disk related activity. To be fair SCSI2SD seek time is (basically) zero, whereas for the real spinning magnetic drives can be in the multi millisecond range. So all in all it is kind of a mixed bag, but the convenience of using the SCSI2SD is definitely a win.

    Don

  9. #9
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    Default

    Quote Originally Posted by AK6DN View Post
    The only downside I have found using SCSI2SD vs (in my case) Seagate 2.1G SCSI drives is raw data transfer. SCSI2SD is async only and on my Emulex UC17 it appears to top out at somewhere about 600KB/sec.
    Has anyone tried using one of the SCSI2SD V6 boards with their PDP-11? They are listed as being much faster than V5 and V5.1 boards, up 10MB/sec using synchronous transfers.

    Tech specs of V5, V5.1, and V6 boards: http://www.codesrc.com/mediawiki/ind...Specifications

    Latest version of SCSI2SD V6: https://store.inertialcomputing.com/...sd-v6-revf.htm

    And someone is selling off some older V6 boards at: https://www.ebay.com/itm/Code-SRC-SC...oAAOSwQqJboW-2

  10. #10
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    Default Scsi2sd v5.0 v5.1 v6.0

    Quote Originally Posted by zamp View Post
    Has anyone tried using one of the SCSI2SD V6 boards with their PDP-11? They are listed as being much faster than V5 and V5.1 boards, up 10MB/sec using synchronous transfers.

    Tech specs of V5, V5.1, and V6 boards: http://www.codesrc.com/mediawiki/ind...Specifications

    Latest version of SCSI2SD V6: https://store.inertialcomputing.com/...sd-v6-revf.htm

    And someone is selling off some older V6 boards at: https://www.ebay.com/itm/Code-SRC-SC...oAAOSwQqJboW-2
    All,
    I have been using SCSI2SD boards with UC07 cards for several years starting with the V3 SCSI2SD cards. The V3 cards work fine but did not have any way to hook up external LEDs. The V4 cards had jumper pins for external LEDs but it was the V5 cards that I used the most having ~10 of them for four PDP-11s including a MINC and three VAXes. When the V6 cards came out I bought two, hoping to see speed increases. One of the two I think has some defect and never worked properly. The other V6 card sometimes had issues that I think the latest V6 firmware may have corrected. At any rate it is working on a VAX ok. The V6 cards have some hardware versions as well and the latest one seems quite stable. I have played with the settings (SCSI-2, Synchronous SCSI, etc) and have NOT seen much performance diference at least with the testing I have done. The V6 card had one advantage that I also thought I might find useful, a means to connect USB thumb drives. The biggest improvement however was accepting standard SDcards instead of microSD cards. I use microSD cards in a SD carrier so that I can move to any other SCSI2SD. It is much easier to change media especially when mounted in some of the 3rd party 3D printed frames. (see photo)

    One thing that can make a very substantial difference in performance is the quality of the microSD card! I've seen differences in performance of a card as large as 250%. In the documentation it seems to indicate that any card works fine but in all versions of the SCSI2SD cards I've seen that higher performance cards do make a difference. Every time I install a SCSI2SD card I install two so that disk to disk backups are possible. I format the cards identically with several virtual drives on the card but having an exact duplicate in case of a boot block getting trashed or installing some software that afterward you wished you hadn't (e.g. VMS with OSI DECnet) has been extremely helpful. With two identical SCSD2SD cards on a system with different microSD cards I did the testing that indicated the significant performance differences. I do use Qbus block mode transfers on the UC07 and that does help performance. I am intrigued by Don's comments on Seagate drives and their performance on PDP-11s. I have seen on the faster MicroVAXes that a good 10,000 Seagate will out perform a SCSI2SD card but haven't tried that on one of my PDP-11/83s.

    I haven't had a microSD card ever fail but on my most important PDPs I did buy a SwissMicro high reliability card that are designed for industrial use. They are very expensive and also fast (on a par with good Class 10 cards) but if you have a system that uses the disk hard they could be worthwhile.

    Right now, I think the best SCSI2SD card is the V5.1 as it has the SDcard format like the V6 but costs roughly the same as the V5 card so you can buy two for close to the same cost as one V6 card.

    Mark
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