ZIP 100 parallel using Palmzip.sys driver

Hardware questions and modifications

ZIP 100 parallel using Palmzip.sys driver

Postby strollin » Fri Oct 03, 2008 11:10 am

Does anyone here have first-hand knowledge of using an Iomega ZIP 100 parallel port attach drive on a PCjr using the palmzip.sys driver? If so, are there any special incantations required to make it work?

I have a ZIP 100 and got the palmzip package from Klaus Peichl. With the driver installed, using DOS 2.1 or 3.3, the jr sees the zip drive and appears to be able to create 3 partitions and format them. However, the partitions are not usable. I cannot copy files or create directories. Sometimes a DIR command says no files are present, other times it will report dozens of files with nonsensical names and weird dates present on a freshly formatted partition.

The zip drive works great on another computer using DOS 3.3, creates and formats the 3 partitions no problem and files can be copied and directories created.

I have tried everything I could think of to get it to work on the jr to no avail. I've tried the various switches for the palmzip driver such as forcing nibble mode as well as adding delays via the /W switch. I even tried it with the V-20 processor as well as the 8088 processor. Either it does not work on the jr without some other modification, or the parallel port sidecar on my jr is defective. Do I need to modify the jr's parallel port to be bi-directional? According to the docs with the driver, bi-directional should improve performance but shouldn't be required.
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Re: ZIP 100 parallel using Palmzip.sys driver

Postby Brutman » Fri Oct 03, 2008 2:35 pm

I've used it. I'll dig it out tonight and let you know what the steps are in detail.

Saturday: Sorry, running late!
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Re: ZIP 100 parallel using Palmzip.sys driver

Postby Brutman » Sun Oct 05, 2008 11:07 am

Ok, I spent way too much time on this. But I've got it ... Short story, you should not need special options.

I used DOS 2.1 with no other device drivers. The machine has a NEC V20 which will affect the speed a little bit. I also have a bi-directional parallel port that will make it faster, but should not affect the basic function. Neither of these differences should cause a problem - I've used PalmZip on a true 8088 with a standard serial port, but on an XT not a Jr.

With just one line (device=palmzip.sys) I was able to detect the Zip drive, format the partitions, and use the drive. The only thing that you need to be careful about is making sure that you use three partitions and use FAT12 on them, otherwise DOS 2.1 does not know what to do. If you use FAT16 you are hosed.

I did some performance tests on it. At one point during the testing the drive seemed to 'go away'. I was not able to use the drive until I pulled the power on it. When it is in this state the drive letters will still be there, but DOS will report errors reading the drive.

The performance test involved writing a 512KB file. With no other device drivers the drive was quite slow - about 60 seconds to create or read the file.

With JrConfig loaded and reserving the lower memory for a RAM disk things speed up quite a bit. The same test took about 30 seconds for both reading and writing. This is to be expected, as now the code was running out of the upper memory above the 128K mark, so it was not fighting with the video controller. It's true - a PCjr without extra memory is about half the speed of what it should be.

You might try using the -w option on Palmzip - it controls delay loops that Palmzip uses. I don't think you need it though. I would check the cable and see if the drive operates reliably on a better machine using the Iomega tools (Guest.Exe).
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Re: ZIP 100 parallel using Palmzip.sys driver

Postby strollin » Sun Oct 05, 2008 4:42 pm

Thanks Mike. I'm at the point where I believe that it just won't work on a jr. The problem you describe of the drive "going away" is pretty much what I experience constantly on the jr. The drive letters are there but no other operations work. The drive's activity light stays on until I pull the power. The activity light will then be off until I try to do something then the light comes on and stays on until I pull the power. Also, once the activity light comes on, it's not possible to eject the disk until I power off the drive and power it back on, then I can eject the disk as long as I don't try any operation from the jr.

I've already tested the drive on another machine and it works fine using either the Iomega drivers or the palmzip driver. I only encounter problems on jr.
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Re: ZIP 100 parallel using Palmzip.sys driver

Postby Brutman » Sun Oct 05, 2008 5:31 pm

Grr. Frustrating, isn't it?

How about other device drivers? What else do you have loaded?

Do you have another parallel port to test with?

Lastly, is your keyboard on batteries or using the cord? (Yes, I just did ask that question ... believe it or not, it can make a difference.) If you are on batteries switch to the keyboard cord and let me know if it improves.

I'm pretty certain that the Jr I used it on at IBM had an 8088 processor, not a NEC V20. I know the XT that I used it on for sure had the Intel and not the NEC V20. This driver definitely does work on the PCjr. My 'hangup' problem happened when I started playing with the -w option to speed things up. The default values should be pretty safe.
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Re: ZIP 100 parallel using Palmzip.sys driver

Postby strollin » Sun Oct 05, 2008 6:53 pm

Doh!!! (Sound of hand smacking forehead)

I finally got it to work. The problem was that I was using the jrconfig device driver to access jr's full memory. If I load jrconfig first, the ZIP drive doesn't work. If I load the palmzip device driver 1st, then jrconfig, it works but then my partitions become C:, D: & E: and the ramdisk becomes F:. I wanted the ramdisk to be C: so I dropped jrconfig and used the pcjrmem and ramdisk device drivers instead. Now everything works as expected.

Performance isn't too bad although when you do a DIR it takes seemingly forever for DOS to calculate the amount of free disk space. I verified that it works with both the 8088 and the V20.

Now that I got it working, next step is to modify the parallel port to make it bi-directional to see what kind of a performance boost I will see.

Finally jr is "usable". Having just a single 360K disk drive makes things a lot harder than they need to be.
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Re: ZIP 100 parallel using Palmzip.sys driver

Postby Brutman » Sun Oct 05, 2008 8:08 pm

You should try with jrconfig loaded first - that works for me.

I'm using Jrconfig.nrd (no ram disk) version 2.14. My config.sys is:

device=\jrconfig.214\jrconfig.nrd -c -t3
device=\palmzip\palmzip.sys
device=\jrconfig.214\lowrd.sys

That lets me use jrconfig and still get the ram disk at the right drive letter (F:)

With DOS 2.1 there isn't much of a delay to compute the free space. On DOS 5 it is horrible ...

If you do the bi-directional modification you can expect about 17KB per second reading and writing. The floppy drive weighs in at about 11KB per second on the same test, so it is marginally faster. Nothing like a real hard drive interface though .. an XT can do about 100KB per second.

Regardless, it is still usable. I was doing a lot of floppy swapping while setting everything up today because my machine is only single drive. You are right .. any form of mass storage is better than a single floppy drive.
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Re: ZIP 100 parallel using Palmzip.sys driver

Postby strollin » Tue Oct 07, 2008 7:30 am

Mike - What do you use to test the read/write speed? I made up a batch file that copies a 545K file from one partition on the drive to another partition and noted the time it took to do that. Takes about 62 secs for the 545k file to be copied. I divided 545k by 62 and get about 8.8k per second or half of what you are saying I should get. Since the copy operation is both a read and a write of the file should I double the 8.8K and figure I'm getting 17.6K?
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Re: ZIP 100 parallel using Palmzip.sys driver

Postby Brutman » Tue Oct 07, 2008 6:11 pm

Yep - you are both reading and writing in that time.

I've got a little benchmark that I wrote that does either a big write or a big read. On an empty diskette or a newly partitioned hard drive head seeking will be minimal, so it will be a good test of the bandwidth of the interface. I'll get it posted sometime.
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Re: ZIP 100 parallel using Palmzip.sys driver

Postby Anonymous Coward » Sat Nov 15, 2008 10:29 am

Is there any hope for getting a Zip Plus drive to work on the Jr? I haven't tried palmzip.sys, but I did try the version of guest.exe that was supposed to work with a regular zip100 parallel port drive and had no luck at all.
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