CCS controller with 8" drive and CP/M - CP/M

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Thread: CCS controller with 8" drive and CP/M

  1. CCS controller with 8" drive and CP/M

    I have a working imsai with a CCS controller attached to two shugart 800-2
    drives. I have been trying to get a system disk that will boot using double
    density format. The system does work fine using single density format.
    I have used both sysgen and CCSysgen on a disk formatted using the ccsinst
    format program. The format works as I can stat the newly formatted disk and it
    show the correct free space for a double density format. Does any know how I can
    get the system to boot on a double density disk? Thanks again.

    Imsai with 64k of memory using a CCS floppy disk controller and a CCS Z80 cpu.

  2. Re: CCS controller with 8" drive and CP/M



    On Jan 28, 1:21 pm, Keith wrote:
    > I have a working imsai with a CCS controller attached to two shugart 800-2
    > drives. I have been trying to get a system disk that will boot using double
    > density format. The system does work fine using single density format.
    > I have used both sysgen and CCSysgen on a disk formatted using the ccsinst
    > format program. The format works as I can stat the newly formatted disk and it
    > show the correct free space for a double density format. Does any know how I can
    > get the system to boot on a double density disk? Thanks again.
    >
    > Imsai with 64k of memory using a CCS floppy disk controller and a CCS Z80 cpu.


    Double density is more demanding of processor speed than single
    density. I have some diagnostic suggestions below. But of course read
    your CCS manual and look over the BOOT and BIOS code carefully. See
    what the differences are between single and double density operation
    on the CCS controller; perhaps a different method is used to delay the
    processor for each byte read. Or maybe you mis-relocated the BIOS or
    something, etc.

    Run memory tests to make sure your memory is sound. It probably is if
    will run CP/M from single density successfully.

    Use DU.COM to examine the sectors of the double-density disks you
    make, to make sure the boot tracks are written OK with the correct
    code. You can check the boot sector and the system tracks. I used to
    use DU to write the boot and system tracks directly, and to patch code
    in them without reassembly, etc. I assume you can read Z80/8080 object
    code; if not keep a op code table handy to translate. The address
    bytes are pretty obvious.

    If your IMSAI front panel is fully working, you can see what actually
    gets loaded into your IMSAI memory. Patch your boot code to stop after
    loading, maybe just a "jump here" instruction. Then walk through
    memory to see what got loaded.

    If your front panel is not fully working, you can hide some kind of
    "monitor" program in the middle of RAM, then jump to it and use your
    terminal to run the "monitor" to check memory. Check Dave Dunfield's
    web site for some small monitor programs, or use IMSAI's very old
    monitor program, or search the Web for such programs.

    Hope these are useful ideas. If they sound crude, they are simply
    appropriate to the technology.

    Herb Johnson

    Herbert R. Johnson, New Jersey USA
    web site
    domain mirror a>
    my email address: hjohnson AAT retrotechnology DOTT com
    if no reply, try in a few days: herbjohnson ATT comcast DOTT net
    "Herb's Stuff": old Mac, SGI, 8-inch floppy drives
    S-100 IMSAI Altair computers, docs, by "Dr. S-100"


  3. Re: CCS controller with 8" drive and CP/M

    Herb Johnson wrote:
    > On Jan 28, 1:21 pm, Keith wrote:
    >
    >> I have a working imsai with a CCS controller attached to two
    >> shugart 800-2 drives. I have been trying to get a system disk
    >> that will boot using double density format. The system does work
    >> fine using single density format. I have used both sysgen and
    >> CCSysgen on a disk formatted using the ccsinst format program.
    >> The format works as I can stat the newly formatted disk and it
    >> show the correct free space for a double density format. Does
    >> any know how I can get the system to boot on a double density
    >> disk? Thanks again.
    >>
    >> Imsai with 64k of memory using a CCS floppy disk controller and
    >> a CCS Z80 cpu.

    >
    > Double density is more demanding of processor speed than single
    > density. I have some diagnostic suggestions below. But of course
    > read your CCS manual and look over the BOOT and BIOS code
    > carefully. See what the differences are between single and double
    > density operation on the CCS controller; perhaps a different
    > method is used to delay the processor for each byte read. Or
    > maybe you mis-relocated the BIOS or something, etc.


    8 inch DD is not feasible with a CPU running under 4 Mhz.

    --
    Chuck F (cbfalconer at maineline dot net)
    Available for consulting/temporary embedded and systems.




  4. Re: CCS controller with 8" drive and CP/M

    Keith wrote:
    >
    > >> I have a working imsai with a CCS controller attached to two
    > >> shugart 800-2 drives. I have been trying to get a system disk
    > >> that will boot using double density format. The system does work
    > >> fine using single density format.....
    > >> Imsai with 64k of memory using a CCS floppy disk controller and
    > >> a CCS Z80 cpu.


    Herb Johnson wrote:

    > > Double density is more demanding of processor speed than single
    > > density. ..


    CBFalconer wrote:
    > .8 inch DD is not feasible with a CPU running under 4 Mhz.
    >


    I'm not sure but I think the CCS Z80 card may be 4MHz. But if it is
    2Mhz or 3MHz, there is still some hope. My colleague
    Bruce Jones investigated this very issue for both the Z80 and the
    8080. His notes, and his source code for the Versafloppy II, are
    available on my Web site at the link below. Read and review
    accordingly. It was also discussed in comp.os.cpm not too long ago.

    http://www.retrotechnology.com/herbs_stuff/s_sd.html

    ...but in any event, the CCS documentation for their floppy controller
    would be clear as to what formats that controller supports with the
    CCS CPU card, at least with CCS code.

    But to avoid abstract arguments, and to take my own advice, I just
    read the CCS 2810 and 2820 Z80 CPU manuals: they run at 2MHz or 4MHz.
    And the CCS 2422 floppy controller manual says it supports single or
    double density.

    http://www.retrotechnology.com/herbs_stuff/d_ccs.html

    Herb Johnson

    Herbert R. Johnson, New Jersey USA
    web site
    domain mirror a>
    my email address: hjohnson AAT retrotechnology DOTT com
    if no reply, try in a few days: herbjohnson ATT comcast DOTT net
    "Herb's Stuff": old Mac, SGI, 8-inch floppy drives
    S-100 IMSAI Altair computers, docs, by "Dr. S-100"




  5. Re: CCS controller with 8" drive and CP/M

    My strong recollection is that eight-inch double density at 2MHz CPU
    speed is possible with a Z80, but not with an 8080 or 8085, for which
    4MHz is required (some of the additional Z80 instructions make it barely
    possible). Of course, if the disk controller does DMA (for example the
    Tarbell double density controller), the processor speed is irrelevant.


    Herb Johnson wrote:
    > Keith wrote:
    >>>> I have a working imsai with a CCS controller attached to two
    >>>> shugart 800-2 drives. I have been trying to get a system disk
    >>>> that will boot using double density format. The system does work
    >>>> fine using single density format.....
    >>>> Imsai with 64k of memory using a CCS floppy disk controller and
    >>>> a CCS Z80 cpu.

    >
    > Herb Johnson wrote:
    >
    >>> Double density is more demanding of processor speed than single
    >>> density. ..

    >
    > CBFalconer wrote:
    >> .8 inch DD is not feasible with a CPU running under 4 Mhz.
    >>

    >
    > I'm not sure but I think the CCS Z80 card may be 4MHz. But if it is
    > 2Mhz or 3MHz, there is still some hope. My colleague
    > Bruce Jones investigated this very issue for both the Z80 and the
    > 8080. His notes, and his source code for the Versafloppy II, are
    > available on my Web site at the link below. Read and review
    > accordingly. It was also discussed in comp.os.cpm not too long ago.
    >
    >
    http://www.retrotechnology.com/herbs_stuff/s_sd.html
    >
    > ..but in any event, the CCS documentation for their floppy controller
    > would be clear as to what formats that controller supports with the
    > CCS CPU card, at least with CCS code.
    >
    > But to avoid abstract arguments, and to take my own advice, I just
    > read the CCS 2810 and 2820 Z80 CPU manuals: they run at 2MHz or 4MHz.
    > And the CCS 2422 floppy controller manual says it supports single or
    > double density.
    >
    > http://www.retrotechnology.com/herbs_stuff/d_ccs.html
    >
    > Herb Johnson
    >
    > Herbert R. Johnson, New Jersey USA
    > web site
    > domain mirror > a>
    > my email address: hjohnson AAT retrotechnology DOTT com
    > if no reply, try in a few days: herbjohnson ATT comcast DOTT net
    > "Herb's Stuff": old Mac, SGI, 8-inch floppy drives
    > S-100 IMSAI Altair computers, docs, by "Dr. S-100"
    >
    >
    >


  6. Getting old hardwares running - (was:Re: CCS controller with 8" drive and CP/M)

    On Sun, 28 Jan 2007 13:21:44 -0500, Keith
    wrote:

    >I have a working imsai with a CCS controller attached to two shugart 800-2
    >drives. I have been trying to get a system disk that will boot using double
    >density format.


    Aren't ALL initial boot tracks, whatever the format, single density?

    Meaning: the beginning of the boot track should load/run, at least!

    Also, re: processor type and speed, isn't a bigger consideration the
    type of memory installed, ie knowing how many wait states it may
    have been set up with, or need to be running?

    DMA is a good thing unless it's killed by too many wait states either
    because of slow memory, or un-necessary ones left over from some
    earlier version, before the hardware got upgraded (happened to me!)

    Old systems were almost never 'plug and play', something lost on
    folks weaned on today's hardwares. A lot of screwing around was
    normal, and being able to read/write assembler essential if you
    wanted to mess with I/O stuff. There simply was no 'one size fits
    all' BIOS, something which was written in assembler.

    If you're not good at assembler, you'll write a crappy BIOS.

    If you don't learn the hardware, especially its limitations, you
    won't get any further than Kildall himself did - staring at the disk
    drive sitting on his dining room table for months before finally
    getting John Torode to build him a working disk drive controller.

    Anybody wanting a working CP/M system would be well advised
    to buy one from somebody who knows how to work on them,
    (for maintainance), and get a demonstration that it's working in
    the first place.

    That includes some proof of properly aligned disk drives running
    at the CORRECT speed. Who cares if it reads it's own? What if
    you want to read actual on-speed, properly aligned ones?

    Far as I know, they aren't making alignment disks any more.
    I'm real damn careful about whose drives I'll stick mine into
    these days. I want them to outlast ME.

    Bill


  7. Re: CCS controller with 8" drive and CP/M

    On 29 Jan 2007 10:16:34 -0800, "Herb Johnson"
    wrote:

    >Keith wrote:
    >>
    >> >> I have a working imsai with a CCS controller attached to two
    >> >> shugart 800-2 drives. I have been trying to get a system disk
    >> >> that will boot using double density format. The system does work
    >> >> fine using single density format.....
    >> >> Imsai with 64k of memory using a CCS floppy disk controller and
    >> >> a CCS Z80 cpu.

    >
    >Herb Johnson wrote:
    >
    >> > Double density is more demanding of processor speed than single
    >> > density. ..

    >
    >CBFalconer wrote:
    >> .8 inch DD is not feasible with a CPU running under 4 Mhz.
    >>

    >
    >I'm not sure but I think the CCS Z80 card may be 4MHz. But if it is
    >2Mhz or 3MHz, there is still some hope. My colleague
    >Bruce Jones investigated this very issue for both the Z80 and the
    >8080. His notes, and his source code for the Versafloppy II, are
    >available on my Web site at the link below. Read and review
    >accordingly. It was also discussed in comp.os.cpm not too long ago.


    The CCS Z80 cpu is 4mhz. Least the CCS I have is.

    >
    >http://www.retrotechnology.com/herbs_stuff/s_sd.html
    >
    >..but in any event, the CCS documentation for their floppy controller
    >would be clear as to what formats that controller supports with the
    >CCS CPU card, at least with CCS code.
    >
    >But to avoid abstract arguments, and to take my own advice, I just
    >read the CCS 2810 and 2820 Z80 CPU manuals: they run at 2MHz or 4MHz.
    >And the CCS 2422 floppy controller manual says it supports single or
    >double density.


    The CCS controller supports 5.25 and 8" single and DD and by default
    3.5" drives to 720/780k format.

    However the 8" DD mode requires the CPU to be able to transfer
    1byte every 16us slower than that and bad things happen (data
    overrun/underrun).

    One page 1-4 of the 2422 manual the required items gleaned from
    the reading was that for DD (8") operation a 4mhz z80 is required
    and the onboard formware also uses z80 instructions and expects to run
    at 4mhz cpu. NOTE: the onboard firmware also expects CCS compatable
    IO for the console.

    Allison

  8. Re: Getting old hardwares running - (was:Re: CCS controller with 8" drive and CP/M)

    On Mon, 29 Jan 2007 13:36:12 -0600, Bill
    wrote:

    >On Sun, 28 Jan 2007 13:21:44 -0500, Keith
    >wrote:
    >
    >>I have a working imsai with a CCS controller attached to two shugart 800-2
    >>drives. I have been trying to get a system disk that will boot using double
    >>density format.


    Things that have to be right...

    Drive must work at least in SD mode.

    CPU must be fast enough to transfer data in DD mode (usually not less
    than 4mhz z80.)

    Memory without wait states helps is your near the limit (slow cpu and
    slow ram are killer) but most memory will run with no waits or at
    worst 1 wait state and at 4mhz z80 that's tolerable.

    IO on the DD version of the boot disk must match the IO in the system.
    Usually by IO I mean the console serial port address and status bits.
    If those do not mach the bios of the DD disk you may see a boot and
    hang or crash.

    >Aren't ALL initial boot tracks, whatever the format, single density?


    No, though some did. The CP/M standard and only standard was
    SSSD 8" all others were vendor specific.

    >Meaning: the beginning of the boot track should load/run, at least!


    No guarentee.

    >Also, re: processor type and speed, isn't a bigger consideration the
    >type of memory installed, ie knowing how many wait states it may
    >have been set up with, or need to be running?


    Both CPU speed and Memory wait states are a factor. Of the two
    the CPU is the hard limiting factor for DD. Most memory that require
    wait stats are either very old (and slow) or only need one wait when
    used at 4mhz (z80). There were many memories that didn't require
    waits at all for 4mhz z80.

    Generally 2mhz 8080 doesnt cut it for DD 8" without real DMA.
    DMA cuts the cpu out of the loop for the data ransfer so CPU
    speed is not a factor.

    8085 is faster than 8080 (3 vs 2mhz). There were faster 8085s
    (5mhz). The 3mhz 8085 is not quite fast enough (without special
    hardware tricks) to do DD 8". The 5mhz part will do it with memory
    that needs one wait state to meet cpu timing.

    >DMA is a good thing unless it's killed by too many wait states either
    >because of slow memory, or un-necessary ones left over from some
    >earlier version, before the hardware got upgraded (happened to me!)


    DMA does not use the CPU and unless the system has a zillion wait
    states ( or enough to exceed 13us per read or write) it's not a
    factor.

    >Old systems were almost never 'plug and play', something lost on
    >folks weaned on today's hardwares. A lot of screwing around was
    >normal, and being able to read/write assembler essential if you
    >wanted to mess with I/O stuff. There simply was no 'one size fits
    >all' BIOS, something which was written in assembler.


    Not always true. They were plug and play within a vendors line.
    This is true for my NS* Horizon, CCS 2200 series, AmproLB+
    and many other vendor integrated systems. However, if you mixing
    cards from several vendors you be come the integrator and the amount
    of work required to make it all play is dependent on what cards and
    vendor support supplied with them.

    >If you're not good at assembler, you'll write a crappy BIOS.


    You don't have to write a crappy one. However you may at first
    pass create a minimal one. There are enough examples and
    good text (The programmers CP/M hand book, Andy Johnson-Laird)
    to assist.

    >If you don't learn the hardware, especially its limitations, you
    >won't get any further than Kildall himself did - staring at the disk
    >drive sitting on his dining room table for months before finally
    >getting John Torode to build him a working disk drive controller.


    Roger that!

    >Anybody wanting a working CP/M system would be well advised
    >to buy one from somebody who knows how to work on them,
    >(for maintainance), and get a demonstration that it's working in
    >the first place.


    Or find one that is at least complete and already integrated.

    >That includes some proof of properly aligned disk drives running
    >at the CORRECT speed. Who cares if it reads it's own? What if
    >you want to read actual on-speed, properly aligned ones?


    Not required but a good thing. Most drives are on speed or
    close enough. Some drive like SA800 have the speed determined
    by use of sychronous AC motors and it's rare they wander far.

    >Far as I know, they aren't making alignment disks any more.
    >I'm real damn careful about whose drives I'll stick mine into
    >these days. I want them to outlast ME.


    Good drives in, good results over time out. SA400/450s were crap!!!


    Allison


  9. Re: CCS controller with 8" drive and CP/M

    Barry Watzman wrote:
    > My strong recollection is that eight-inch double density at 2MHz CPU
    > speed is possible with a Z80, but not with an 8080 or 8085, for which
    > 4MHz is required (some of the additional Z80 instructions make it barely
    > possible).


    CBFalconer wrote:
    >You need 4 Mhz for an 8080. The z80 can do slightly better by
    > using the NMI instead of a wait state. I once built a system that
    > could input 56 bits in 84 uS on an 8008, and that was really
    > tight. It took a presync operation and hardware.


    Chuck and Barry are mosty correct, but not absolutely so. As I posted,
    I have on my Web site the work of Bruce Jones. His docs and code
    fragments are on my site. He shows how you can TRY to do double
    density at 2MHz. It's a marginal proposition. One method is that you
    "unroll" the read and write loops to save time normally used in the
    "jump" instruction.There are methods to manage the FDC chip: Bruce
    goes through them. Read the discussion about his results, that too is
    on my Web site.

    This issue used to come up every few years in comp.os.cpm; it's on my
    site so I can say "go there", and so that others may find it with a
    Web search. Read the discussion, on my site, then post. If you dispute
    the results and discusion, and make a good case about it, I'l add your
    dispute to the document. That helps others, another day.

    http://www.retrotechnology.com/herbs_stuff/sdfdc.html

    That said, it's moot for "Keith" as he has a 4MHz Z80 card; and the
    CCS manuals will inform him about what he wants to do. CCS already
    provided (I believe but I dont' know for a fact) booting from double
    density. I have the manuals, copies are available from me, but I
    usually let the buyer read them. Same applies to what's on my site, I
    guess I'm consistent in that regard.

    Herb Johnson

    Herbert R. Johnson, New Jersey USA
    web site
    domain mirror a>
    my email address: hjohnson AAT retrotechnology DOTT com
    if no reply, try in a few days: herbjohnson ATT comcast DOTT net
    "Herb's Stuff": old Mac, SGI, 8-inch floppy drives
    S-100 IMSAI Altair computers, docs, by "Dr. S-100"


  10. Re: CCS controller with 8" drive and CP/M

    These is a 2/4 mhz switch on the CCS z80 card. It was on 2 mhz as I was testing
    it and forgot about it. I have tried using it at 4mhz and do get better results.
    I think I have found the problem with the CCS controller booting DD disk. The
    default ccsbios requires the first track to be single density and 128 byte
    sectors to be IBM compatible. If you format a double density disk using their
    format program it will always format the first track in single density with128
    byte sectors. The remaining tracks can be formatted double density and
    128/256/512/1024 byte sectors. If you do a stat on the disk it does show the
    higher density even with the first track formatted as SD/128. If I do a sysgen
    using their program it appears to work(Get CPM 56 boot message) but does not
    boot. If I boot the system using another disk and then use this DD disk in drive
    A and do the Ctrl-C it works fine with 400k+ density. CCS boot requires a
    program called rlocbios.com to load at boot time. This program is required
    because the ccsbios is to big to fit on the boot sectors. Because the remaining
    tracks are double density it hangs trying to read the rlocbios.com program.

    recap because I'm sure I'm making myself clear.

    SD disk boots then loads a program called rlocbios.com
    DD disk boots off SD/256 track one then reads remainder of disk using DD tracks
    including rlocbios.com

    It disk controller is a 1792 type controller


    CBFalconer wrote:

    >Herb Johnson wrote:
    >> CBFalconer wrote:
    >>

    >... had to snip lots, because the quoting was all fouled ...
    >>
    >>> .8 inch DD is not feasible with a CPU running under 4 Mhz.

    >>
    >> I'm not sure but I think the CCS Z80 card may be 4MHz. But if it is
    >> 2Mhz or 3MHz, there is still some hope. My colleague
    >> Bruce Jones investigated this very issue for both the Z80 and the
    >> 8080. His notes, and his source code for the Versafloppy II, are
    >> available on my Web site at the link below. Read and review
    >> accordingly. It was also discussed in comp.os.cpm not too long ago.
    >>
    >>
    http://www.retrotechnology.com/herbs_stuff/s_sd.html
    >
    >You need 4 Mhz for an 8080. The z80 can do slightly better by
    >using the NMI instead of a wait state. I once built a system that
    >could input 56 bits in 84 uS on an 8008, and that was really
    >tight. It took a presync operation and hardware.


  11. Re: CCS controller with 8" drive and CP/M


    "Herb Johnson" wrote in message
    news:1170018103.787502.62000@v33g2000cwv.googlegro ups.com...
    >
    >
    > On Jan 28, 1:21 pm, Keith wrote:
    >> I have a working imsai with a CCS controller attached to two shugart
    >> 800-2
    >> drives. I have been trying to get a system disk that will boot using
    >> double
    >> density format. The system does work fine using single density format.
    >> I have used both sysgen and CCSysgen on a disk formatted using the
    >> ccsinst
    >> format program. The format works as I can stat the newly formatted disk
    >> and it
    >> show the correct free space for a double density format. Does any know
    >> how I can
    >> get the system to boot on a double density disk? Thanks again.
    >>
    >> Imsai with 64k of memory using a CCS floppy disk controller and a CCS Z80
    >> cpu.

    >
    > Double density is more demanding of processor speed than single
    > density. I have some diagnostic suggestions below. But of course read
    > your CCS manual and look over the BOOT and BIOS code carefully. See
    > what the differences are between single and double density operation
    > on the CCS controller; perhaps a different method is used to delay the
    > processor for each byte read. Or maybe you mis-relocated the BIOS or
    > something, etc.
    >
    > Run memory tests to make sure your memory is sound. It probably is if
    > will run CP/M from single density successfully.
    >
    > Use DU.COM to examine the sectors of the double-density disks you
    > make, to make sure the boot tracks are written OK with the correct
    > code. You can check the boot sector and the system tracks. I used to
    > use DU to write the boot and system tracks directly, and to patch code
    > in them without reassembly, etc. I assume you can read Z80/8080 object
    > code; if not keep a op code table handy to translate. The address
    > bytes are pretty obvious.
    >
    > If your IMSAI front panel is fully working, you can see what actually
    > gets loaded into your IMSAI memory. Patch your boot code to stop after
    > loading, maybe just a "jump here" instruction. Then walk through
    > memory to see what got loaded.
    >
    > If your front panel is not fully working, you can hide some kind of
    > "monitor" program in the middle of RAM, then jump to it and use your
    > terminal to run the "monitor" to check memory. Check Dave Dunfield's
    > web site for some small monitor programs, or use IMSAI's very old
    > monitor program, or search the Web for such programs.
    >
    > Hope these are useful ideas. If they sound crude, they are simply
    > appropriate to the technology.
    >
    > Herb Johnson
    >
    > Herbert R. Johnson, New Jersey USA
    > web site
    > domain mirror > a>
    > my email address: hjohnson AAT retrotechnology DOTT com
    > if no reply, try in a few days: herbjohnson ATT comcast DOTT net
    > "Herb's Stuff": old Mac, SGI, 8-inch floppy drives
    > S-100 IMSAI Altair computers, docs, by "Dr. S-100"
    >

    The IMSAI DIO series of memory mapped controllers handled Double Density
    just fine with the MPU-C 8085-based processor running at 3 MHz., and just as
    well with the original IMSAI MPU-A running at 2 MHz. We sold a boatload of
    disk subsystems to first and second generation IMSAI system owners. Our
    double-density formats included 256, 512, and 1024 (long sector) sector
    lengths. The mid-1977 second generation controllers closely followed the
    IBM 3740 formats and subsequent variants for media read/write compatibility.
    The original DIO-A of early 1977 used a proprietary double density format
    which was unique to IMSAI.

    For the record, the original IMSAI IFM/FIB intelligent DMA disk controller
    of mid-1976 was debugged and rendered eminently usable and reliable by Glen
    Ewing, consultant to IMSAI and fellow instructor with Gary Kildall at the
    Naval Postgraduate school in Monterey, CA. It was Glen who urged and
    collaborated with Gary to take the I/O specific controls out of the original
    BDOS and port them as user-configurable modules to be incorporated into the
    BIOS instead. It was Glen's vision and capabilities, as well as the
    marketing genius of IMSAI's then Marketing Director Seymour Rubenstein that
    made IMSAI the first commercial user to offer CP/M to the public (with the
    first and only unlimited distribution rights) in mid-1976. I still have one
    of Kildall's original CP/M development disks on 8" single-density media, as
    well as the original Kildall-initialed hard copy listings of source code
    that was released to IMSAI under license number 3. I will gladly part with
    same for an impressive stack of currency to that unique collector of the
    rarest and most unusual of computer collectibles!

    Regards,

    -Thomas "Todd" Fischer



  12. Re: Getting old hardwares running -

    No; that is up to the system implementer. It's common, but not
    absolutely universal or required.

    Bill wrote:

    >
    > Aren't ALL initial boot tracks, whatever the format, single density?
    >


  13. Re: CCS controller with 8" drive and CP/M

    The Z80 can do a LOT better because of it's additional instructions, not
    NMI. A Z80 can do 8-inch double density at 2MHz. What makes it
    possible are block I/O, the REP (repeat instruction) and it's loop
    instructions that the 8080 and 8085 don't have.


    CBFalconer wrote:
    > Herb Johnson wrote:
    >
    > You need 4 Mhz for an 8080. The z80 can do slightly better by
    > using the NMI instead of a wait state. I once built a system that
    > could input 56 bits in 84 uS on an 8008, and that was really
    > tight. It took a presync operation and hardware.
    >


  14. Re: CCS controller with 8" drive and CP/M

    I have a few configuations using the CCS 2422. As stated you must have
    a Z80 running at 4Mhz to boot with 8" DD disks. You actually can use 2
    Mhz with a 5 1/4" DD. Also CCBOOT, and as stated before, the
    firmware, are all in Z80 code. As an FYI, you have the option of
    putting the CCBIOS on the system tracks of double density disks
    instead of using the relocatable bios (RLOCBIOS). There is a procedure
    to do this and suppress the autload feature for RLOCBIOS. Of course to
    use the full BIOS with SD disks you must use the RLOCBIOS feature.

    If I can help more, please let me know. The systems I have are running
    very well.

    Rich

    On Jan 29, 3:17 pm, Keith wrote:
    > These is a 2/4 mhz switch on the CCS z80 card. It was on 2 mhz as I was testing
    > it and forgot about it. I have tried using it at 4mhz and do get better results.
    > I think I have found the problem with the CCS controller booting DD disk. The
    > default ccsbios requires the first track to be single density and 128 byte
    > sectors to be IBM compatible. If you format a double density disk using their
    > format program it will always format the first track in single density with128
    > byte sectors. The remaining tracks can be formatted double density and
    > 128/256/512/1024 byte sectors. If you do a stat on the disk it does show the
    > higher density even with the first track formatted as SD/128. If I do a sysgen
    > using their program it appears to work(Get CPM 56 boot message) but does not
    > boot. If I boot the system using another disk and then use this DD disk in drive
    > A and do the Ctrl-C it works fine with 400k+ density. CCS boot requires a
    > program called rlocbios.com to load at boot time. This program is required
    > because the ccsbios is to big to fit on the boot sectors. Because the remaining
    > tracks are double density it hangs trying to read the rlocbios.com program.
    >
    > recap because I'm sure I'm making myself clear.
    >
    > SD disk boots then loads a program called rlocbios.com
    > DD disk boots off SD/256 track one then reads remainder of disk using DD tracks
    > including rlocbios.com
    >
    > It disk controller is a 1792 type controller
    >
    >
    >
    > CBFalconer wrote:
    > >Herb Johnson wrote:
    > >> CBFalconer wrote:

    >
    > >... had to snip lots, because the quoting was all fouled ...

    >
    > >>> .8 inch DD is not feasible with a CPU running under 4 Mhz.

    >
    > >> I'm not sure but I think the CCS Z80 card may be 4MHz. But if it is
    > >> 2Mhz or 3MHz, there is still some hope. My colleague
    > >> Bruce Jones investigated this very issue for both the Z80 and the
    > >> 8080. His notes, and his source code for the Versafloppy II, are
    > >> available on my Web site at the link below. Read and review
    > >> accordingly. It was also discussed in comp.os.cpm not too long ago.

    >
    > >>
    http://www.retrotechnology.com/herbs_stuff/s_sd.html
    >
    > >You need 4 Mhz for an 8080. The z80 can do slightly better by
    > >using the NMI instead of a wait state. I once built a system that
    > >could input 56 bits in 84 uS on an 8008, and that was really
    > >tight. It took a presync operation and hardware.- Hide quoted text -- Show quoted text -



  15. Re: CCS controller with 8" drive and CP/M

    Keith wrote:
    >
    > These is a 2/4 mhz switch on the CCS z80 card. It was on 2 mhz as I was testing
    > it and forgot about it. I have tried using it at 4mhz and do get better results.


    Please don't top-post. Your answer belongs after (or intermixed
    with) the snipped material you quote. Snipping removes anything
    not germane to your reply. See the following links:

    --
    Some informative links:



    (taming google)
    (newusers)



  16. Re: CCS controller with 8" drive and CP/M

    Re: "with the first and only unlimited distribution rights"

    That part is incorrect (well, "first" IS correct, but "only" is not).
    Digital Research offered all OEMs the option to purchase unlimited
    distribution rights (no subsequent per-copy royalties) at least into the
    1980's, if not until the company ceased to exist. We bought such rights
    while I was with Zenith (Heathkit). The price was high and increased
    several times with later versions of CP/M, but it was available and was
    a good deal for OEMs who would ship many thousands to tens (or hundreds)
    of thousands of copies. I'm thinking that we paid $35,000 or so for
    such rights to CP/M 2.2.

    I also don't believe (am certain, in fact) that you can do double
    density 8" on a disk controller without DMA or an onboard sector buffer
    using a 2MHz 8080 CPU. There is no way to get through the loop in the
    available time. I believe that it is possible with a 2MHz Z-80, and I'm
    not sure about an 8085 (at either 2MHz or 3MHz).

    Barry Watzman


    Thomas "Todd" Fischer wrote:
    > "Herb Johnson" wrote in message
    > news:1170018103.787502.62000@v33g2000cwv.googlegro ups.com...
    >>
    >> On Jan 28, 1:21 pm, Keith wrote:
    >>> I have a working imsai with a CCS controller attached to two shugart
    >>> 800-2
    >>> drives. I have been trying to get a system disk that will boot using
    >>> double
    >>> density format. The system does work fine using single density format.
    >>> I have used both sysgen and CCSysgen on a disk formatted using the
    >>> ccsinst
    >>> format program. The format works as I can stat the newly formatted disk
    >>> and it
    >>> show the correct free space for a double density format. Does any know
    >>> how I can
    >>> get the system to boot on a double density disk? Thanks again.
    >>>
    >>> Imsai with 64k of memory using a CCS floppy disk controller and a CCS Z80
    >>> cpu.

    >> Double density is more demanding of processor speed than single
    >> density. I have some diagnostic suggestions below. But of course read
    >> your CCS manual and look over the BOOT and BIOS code carefully. See
    >> what the differences are between single and double density operation
    >> on the CCS controller; perhaps a different method is used to delay the
    >> processor for each byte read. Or maybe you mis-relocated the BIOS or
    >> something, etc.
    >>
    >> Run memory tests to make sure your memory is sound. It probably is if
    >> will run CP/M from single density successfully.
    >>
    >> Use DU.COM to examine the sectors of the double-density disks you
    >> make, to make sure the boot tracks are written OK with the correct
    >> code. You can check the boot sector and the system tracks. I used to
    >> use DU to write the boot and system tracks directly, and to patch code
    >> in them without reassembly, etc. I assume you can read Z80/8080 object
    >> code; if not keep a op code table handy to translate. The address
    >> bytes are pretty obvious.
    >>
    >> If your IMSAI front panel is fully working, you can see what actually
    >> gets loaded into your IMSAI memory. Patch your boot code to stop after
    >> loading, maybe just a "jump here" instruction. Then walk through
    >> memory to see what got loaded.
    >>
    >> If your front panel is not fully working, you can hide some kind of
    >> "monitor" program in the middle of RAM, then jump to it and use your
    >> terminal to run the "monitor" to check memory. Check Dave Dunfield's
    >> web site for some small monitor programs, or use IMSAI's very old
    >> monitor program, or search the Web for such programs.
    >>
    >> Hope these are useful ideas. If they sound crude, they are simply
    >> appropriate to the technology.
    >>
    >> Herb Johnson
    >>
    >> Herbert R. Johnson, New Jersey USA
    >> web site
    >> domain mirror >> a>
    >> my email address: hjohnson AAT retrotechnology DOTT com
    >> if no reply, try in a few days: herbjohnson ATT comcast DOTT net
    >> "Herb's Stuff": old Mac, SGI, 8-inch floppy drives
    >> S-100 IMSAI Altair computers, docs, by "Dr. S-100"
    >>

    > The IMSAI DIO series of memory mapped controllers handled Double Density
    > just fine with the MPU-C 8085-based processor running at 3 MHz., and just as
    > well with the original IMSAI MPU-A running at 2 MHz. We sold a boatload of
    > disk subsystems to first and second generation IMSAI system owners. Our
    > double-density formats included 256, 512, and 1024 (long sector) sector
    > lengths. The mid-1977 second generation controllers closely followed the
    > IBM 3740 formats and subsequent variants for media read/write compatibility.
    > The original DIO-A of early 1977 used a proprietary double density format
    > which was unique to IMSAI.
    >
    > For the record, the original IMSAI IFM/FIB intelligent DMA disk controller
    > of mid-1976 was debugged and rendered eminently usable and reliable by Glen
    > Ewing, consultant to IMSAI and fellow instructor with Gary Kildall at the
    > Naval Postgraduate school in Monterey, CA. It was Glen who urged and
    > collaborated with Gary to take the I/O specific controls out of the original
    > BDOS and port them as user-configurable modules to be incorporated into the
    > BIOS instead. It was Glen's vision and capabilities, as well as the
    > marketing genius of IMSAI's then Marketing Director Seymour Rubenstein that
    > made IMSAI the first commercial user to offer CP/M to the public (with the
    > first and only unlimited distribution rights) in mid-1976. I still have one
    > of Kildall's original CP/M development disks on 8" single-density media, as
    > well as the original Kildall-initialed hard copy listings of source code
    > that was released to IMSAI under license number 3. I will gladly part with
    > same for an impressive stack of currency to that unique collector of the
    > rarest and most unusual of computer collectibles!
    >
    > Regards,
    >
    > -Thomas "Todd" Fischer
    >
    >


  17. Re: CCS controller with 8" drive and CP/M

    Please don't tell us how to post. Your opinions on how one "should"
    post are just your own opinions and nothing more.


    CBFalconer wrote:
    > Keith wrote:
    >> These is a 2/4 mhz switch on the CCS z80 card. It was on 2 mhz as I was testing
    >> it and forgot about it. I have tried using it at 4mhz and do get better results.

    >
    > Please don't top-post. Your answer belongs after (or intermixed
    > with) the snipped material you quote. Snipping removes anything
    > not germane to your reply. See the following links:
    >


  18. Re: CCS controller with 8" drive and CP/M

    Barry Watzman wrote:
    > CBFalconer wrote:
    >>

    .... snip ...
    >>
    >> Please don't top-post. Your answer belongs after (or intermixed
    >> with) the snipped material you quote. Snipping removes anything
    >> not germane to your reply. See the following links:

    >
    > Please don't tell us how to post. Your opinions on how one "should"
    > post are just your own opinions and nothing more.


    We are aware that you refuse to follow standard practice, however
    please do not interfere with advising newbies of proper usenet
    protocol.

    --


    "A man who is right every time is not likely to do very much."
    -- Francis Crick, co-discover of DNA
    "There is nothing more amazing than stupidity in action."
    -- Thomas Matthews


  19. Re: CCS controller with 8" drive and CP/M

    CBFalconer wrote:
    >
    > 8 inch DD is not feasible with a CPU running under 4 Mhz.


    On the platform in question, perhaps. However, I own several
    controllers that will cheerfully run 8" DD on a 1.02Mhz. Apple ][.

    Steve

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