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Thread: FreHD on Model II/12/16/16B/6000 - FIRST ATTEMPT

  1. #1
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    Default FreHD on Model II/12/16/16B/6000 - FIRST ATTEMPT

    Yesterday I finally connected FreHD to the Model 16B via the Type 2 HDC.

    As you will see in the video, all was going fine until the reboot at the end, and the system just locks up while loading the OS.



    I used FreHD firmware 2.14, a special version of the FreHD GAL which has all the extra features of FreHD removed (essentially making FreHD a pure hard drive with no RTC, etc.) The DOS used is TRSDOS 2.0 with Hard Drive Initialisation 4.1

    Does anyone know for sure whether this DOS is for an 8meg drive? It counts cylinders up to 1024 which is confusing..

    I may need a more up to date DOS... TRSDOS 2.0 / HD Init 4.1 dates back to 1981/82 so maybe something newer?

    Any thoughts or tech help would be much appreciated.

    Ian.
    *There is never a charge for Tech Support even if you don't purchase from me - We are Enthusiasts Helping Other Enthusiast and that is just the way it is

  2. #2
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    Tim Mann has LS-DOS 6.3.1A for Model II/12/16/6000 http://www.tim-mann.org/misosys.html. Don't know if that would help.

    Mike

  3. #3
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    Thanks Mike, I also have that but it lacks HD drivers. It would be good to get it going so that it's consistent with other TRS-80s, but I think the first step is to get it running as a TRSDOS system.

    For people who want to try to replicate the computer/FreHD setup, you need to burn a new GAL with the jed file HERE: FreHD_MII-2nd.jed

    And update the PIC firmware to 2.14: FreHD_214.hex

    Ian.
    *There is never a charge for Tech Support even if you don't purchase from me - We are Enthusiasts Helping Other Enthusiast and that is just the way it is

  4. #4
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    Hi Ian

    Great job you have done so far. I was thinking about this way of attacking this problem for a long time.
    I'am searching for more than half a year for a Type II HDC.
    It seems to me that they are very hard to find, or not at all.

    If you succeed in getting it to work, have you thought about duplicating the HDC, as without it
    there will be very few intrest in starting to participate in this project.

    I was thinking about a different approach as the Type II HDC controller, as you have proven, is a duplicate of
    the model 4 HD interface.

    If you use the El-Cheapo interface, I think it would be much easier to connect it to the Model II up to the model 16.
    All the operating systems has harddisk support in it, and the software to use it is very much available.

    There is many harddisk setup software, format software and utilities.
    There is more knowhow available at many users.

    I think this whole project needs a easy way to get a model II HDC type 2.

    I whish you a lot of succes with this project.

  5. #5

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    A couple of suggestions. Can you try one of the Z80 CP/M boot disks like Lifeboat or P&T? If I recall, trsdos was rather picky about hard drive geometry. Can you force it to 6 heads 306 cylinders and try again?

    Edit: This version of TRS-DOS may only support 8 meg disk geometry. Try this (from the manual):
    Code:
    HARD DISK 
    
    The TRS-80 Hard Disk Drive is organized into 256 
    "cylinders". Each cylinder is made up of four tracks that 
    have the same radius on each of the four surfaces (4 * 256= 
    1024 total tracks per hard disk). 
    
    Each track contains 34 sectors, numbered 1-34. Each sector 
    contains 256 bytes. 
    
    The total capacity of a hard disk is: 
    
    (1024 * 34 * 256) = 8,912,896 bytes
    TRSDOS-II supports arbitrary hard drives using the FORMAT command. See http://www.vintagecomputer.net/fjkra...RefMan_1-2.pdf, page 74 of the PDF.
    Last edited by kb2syd; March 3rd, 2015 at 06:13 AM.

  6. #6

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    Quote Originally Posted by Hans01 View Post
    If you succeed in getting it to work, have you thought about duplicating the HDC, as without it
    there will be very few intrest in starting to participate in this project.
    I have to concur with Hans. Although, I say full speed ahead Ian, this is an awesome first step and I am sure to buy one, i have yet to find a HDC for my Model II. Finding the hard drives has been easier than the controller.

  7. #7

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    The type 2 HDC looks pretty simple. I'll have to pull the tech ref for it and confirm. Looks like a CTC, 16k of RAM and some glue to hold it all together. Thoughts?

  8. #8

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    I'm a little confused by what I'm seeing in this video. I'm still relatively new to the Model II world, so please bear with me.

    I see the system in the video is running TRSDOS 2.0a. From what I've read, TRSDOS 2.0a did not support hard drives. In fact, I've read in the manuals that the thinline drives on the Model 12/16/6000 required TRSDOS 2.0b due to the fact that the drives don't run continuously.

    Model IIs supposedly require TRSDOS-HD for harddrive support or TRSDOS-II 4.x for HD support on an 68k upgraded Model II/12 or 16/6000.

    Am I correct in my understanding?

    Update: After a little more research I see now why you could format and build a HD using TRS-DOS 2.0 as depicted in Ian's video. Apparently the 4.0 versions of TRSDOS-II required the HD to be setup using TRSDOS 2.0 before installing TRSDOS-II. 4.2 and later TRSDOS-II did not have this limitation.

    See http://fjkraan.home.xs4all.nl/comp/t...S_versions.txt
    Last edited by pski; March 3rd, 2015 at 08:16 PM.

  9. #9
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    Yes, early days at the moment.

    My knowledge and resources (more on that below) are rather limited compared to the I/III/4 systems so this project will require much more collaboration from you good forum members as I learn about these systems at the same time as experimenting with details until it works. Yesterdays video is just the start.

    Re. Type 2 HDC, yep - it's a rare one, which makes this project more of a "I just want to see it work" rather than a volume seller that every user can just buy and plug in. Most enthusiasts who have acquired 8in systems over the years have the Type 2 HDC in their collection, some may not even know it's in there. I feel sorry for those 8in enthusiasts who are starting out collecting now, as they are expensive to buy and are easily damaged in transit. Even more so as the plastic cases get brittle with age. I have looked at the Type 2 HDC but it's just too sophisticated to reverse engineer and build new ones at anything approaching reasonable costs. Type 2 HDC contains some 40 ICs, one of which being a hard-to-find Z80A CTC.

    Re. Resources: To start the testing I can logically only start with what disks I have on hand. So the first test is done with the only TRSDOS HD disk I had, which the more I look into it seems to be related to the old 8meg hard drives. It's a promising start, but I need to obtain newer versions of the operating systems, to proceed further. I have been reliably tipped that I need 4.2.1 , or .3, .5, .7, .9 which are the versions for the WD1010 HDDs which FreHD emulates.

    Anyone able to ship me a copy of the 4.2.x OS?

    Cheers,

    Ian.
    *There is never a charge for Tech Support even if you don't purchase from me - We are Enthusiasts Helping Other Enthusiast and that is just the way it is

  10. #10

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    http://www.vintagecomputer.net/disk_images/TRS80_8in/

    26-4912.IMD

    It's 4.2 for the Model 12 so it might work.

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