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Re: 8800BT

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  • Larry D. Pyeatt
    Hi Tom, Thanks for writing. I ll try to answer your questions in order... I got the flat switches from ebay. They look like the original, except for the
    Message 1 of 7 , Aug 29, 2006
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      Hi Tom,

      Thanks for writing. I'll try to answer your questions in order...

      I got the flat switches from ebay. They look like the original, except
      for the solder lugs. The replacements would not fit on the PC board.
      Also, one of the switches was a momentary. So, I took the switch
      bodies apart and swapped the levers. New levers on the old bodies,
      then put them back on the board. Viola!

      I didn't think they could re-key the locks, but I took it to a local
      locksmith, and they had it done in a few hours, for $12.

      The capacitors took some searching. I found the big one at TEDSS.com.
      They did not have the 15V 95000mfd cap, but they did have a 16V one.
      I could not find exact replacements for the 2200mfd, but they had a part
      that was blue and similar in size. Here are the TEDSS part numbers:
      CG953U016X4C and EIKEA601

      I got the B model processor board.

      I found the documentation on the floppy controller, and got
      the chips back on them. The only thing I'm missing now is the big
      chip on the Turnkey Module, and you told me what it is!
      THANKS!

      I found the docs on the 88-CLG modification. This could be a problem.
      All I have is a single 16K RAM board. I guess I have four options:
      1) Get three more 16K RAM boards.
      2) Build a 64K board.
      3) Change something so the stack is located at the 3FFF, or map my 16K
      board to reside at C000-FFFF. (is the stack location set by firmware?)
      4) Undo the modification.
      I'm thinking that 4) is the best way to go. Any suggestions?

      I got what I think is an FD 4XX drive, with cabinet and all. The
      controllers
      were missing a 7411 and a 7420. That was no problem, once I found out
      what the parts were supposed to be. If a flat ribbon cable will work, then
      I can make one. The construction details are in the documentation
      that I got on-line.

      I am just about ready to order some floppies.


      W. Tom Sanderson wrote:

      >>I found an 8800bt in a dumpster about 15 years ago
      >
      > Congratulations!
      >
      >>Replaced the broken front panel switches
      >
      > Were you able to find the flat switches?
      >
      >> had the lock re-keyed to fit the keys.
      >
      > That's good to know. I have several original key types that I can
      > copy. I didn't know the locks can be changed.
      >
      >>Then I replaced all the capacitors in the power supply, even though
      > they didn't seem to have leaked.
      >
      > The original one seem to have a long life. Where did you find
      > replacements? I haven't looked too hard, but haven't had luck in
      > Albuquerque.
      >
      >>Last night I turned it on with no boards, just to test the power
      > supply. It worked! All three voltages look good.
      > Did you notice that that there are three options for connecting the
      > transformer? One for <= six boards, one for 7-12 boards, and another
      > for 13-18 boards.
      >
      >>The processor board is missing, so I bought one from EBay.
      >
      > There are two types. The B models have a newer design.
      >
      >> Some of the other boards have missing chips.
      >
      > Which ones? The manuals should have parts lists. I can help if you
      > identify the boards.
      >
      >
      >>part that I need right now is a 24-pin wide DIP that goes next to the
      > SENSE switches
      >
      > Motorola 6850 UART
      >
      > My best guess is that the missing chip has something to do with the
      > serial port.
      >
      > Good guess. The port address is switch selectable and must not be the
      > same as a 2SIO board, if you have one.
      >
      > The Turnkey Module has been modified. Traces are cut and several
      > jumpers installed. It looks like the onboard RAM has been disabled.
      > I'm not
      > sure if this has anything to do with the missing chip, but it does not
      > look like it to me.
      > 88-CLG modification. See virtualaltair.com turnkey page. RAM is
      > disabled for business system needing 64K. The modified board requires
      > 64K RAM. The stack is now on the top memory board instead of the
      > turnkey. After booting, output to sense switch port (FF) and the proms
      > disappear so you have a full 64K RAM.
      >
      >>On another note.. Does anyone have any idea how much a Pertec 8"
      > floppy drive should cost, or where I could get one?
      >
      > I have some empty MITS drive cabinets, but haven't decided on price.
      > The dives are a problem. The plastic bezels and doors break easy. The
      > drives are still used in CNC machines and flight simulators. A
      > refurbished drive may cost $750. The drives are sometimes available on
      > eBay and most people don't know the cost of a bare drive. Ebay prices
      > may be lower than $750 for drive and cabinets. There are several
      > variations. Two door types for the FD 4XX DC drives (white &
      > white/Aluminum). Black bezels are FD 5XX AC drives. Single drive
      > cabinets may be 8800/8800a style or may have an 8800b style face
      > plate. The 3202 dual drive cabinet has two FD5XX drives.
      >
      >>I have the controller cards (with three missing chips), but no drive
      > or cable.
      >
      > The controller pairs I have seem to be reliable. Hardware guys worry
      > about some "one-shots". There are two types of cables. The older type
      > has twisted pairs of colored wires. The newest types are flat ribbon
      > cable. Which chips are missing?
      >
      >>I'm also looking for someone to copy their software onto floppys for
      > me assuming I can find a floppy drive (I'll provide the floppies). Are
      > there copyright issues with that?
      >
      > I have copies of most software. There are copyright issues (Microsoft
      > Software like BASIC or Fortran plus CP/M). I have blank disks too
      > (32-hard sector).
      >
      >>I am having a lot of fun working on this old thing.
      >
      > That is how it started. The Altair was a "Hobbyist" computer when it
      > started. Your B model was for "Business Systems" (64K & original
      > Peachtree accounting).
      >
      > Regards,
      >
      > Tom Sanderson
      > www.virtualaltair.com <http://www.virtualaltair.com>
      >
      >
      >


      --
      Larry D. Pyeatt, PhD.
      pyeatt@...
      http://www.cs.ttu.edu/~pyeatt
    • Steve
      Larry, For further information on Altair s front panel switches, and for possible sources, look in the FILES folder, at FILES STEVE S FILES Sources for
      Message 2 of 7 , Aug 29, 2006
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        Larry,

        For further information on Altair's front panel switches, and for
        possible sources, look in the FILES folder, at
        FILES > STEVE'S FILES > 'Sources for 8800b toggle switches.pdf' .

        A Turnkey board that has the System Kludge (88-SYS CLG) mod installed
        should work OK with less than 64K, if you have some additional RAM
        at the top. For example, a 4K board addressed from 60K to 64K. If
        you can confirm that your board actually has this mod installed
        (there were a couple of other mods that were similar), then it
        shouldn't be too hard to un-mod it. If you need a better copy of the
        instruction sheet than what Tom has posted, I'll upload a bigger one
        to our FILES folder. Andy Kessel may have some suggestions too.

        If you plan to use Altair Disk BASIC, I think you'll need at least
        32K of RAM for the early versions and 48K for later versions.

        Pertecs FD400 drives usually had a white front door and used a
        stepper motor to spin the disk. The FD500s had black doors and a
        115VAC spindle motor , which was much more reliable. If the 400's
        stepper stalled, the TIP driver transistors would usually smoke if
        power wasn't quickly removed by opening the door. Other than the
        spindle motors, the drives were interchangeable.

        Steve
        ===============================

        --- In altaircomputerclub@yahoogroups.com, "Larry D. Pyeatt"
        <pyeatt@...> wrote:
        >
        >
        > Hi Tom,
        >
        > Thanks for writing. I'll try to answer your questions in order...
        >
        > I got the flat switches from ebay. They look like the original,
        except
        > for the solder lugs. The replacements would not fit on the PC
        board.
        > Also, one of the switches was a momentary. So, I took the switch
        > bodies apart and swapped the levers. New levers on the old bodies,
        > then put them back on the board. Viola!
        >
        > I didn't think they could re-key the locks, but I took it to a local
        > locksmith, and they had it done in a few hours, for $12.
        >
        > The capacitors took some searching. I found the big one at
        TEDSS.com.
        > They did not have the 15V 95000mfd cap, but they did have a 16V one.
        > I could not find exact replacements for the 2200mfd, but they had a
        part
        > that was blue and similar in size. Here are the TEDSS part numbers:
        > CG953U016X4C and EIKEA601
        >
        > I got the B model processor board.
        >
        > I found the documentation on the floppy controller, and got
        > the chips back on them. The only thing I'm missing now is the big
        > chip on the Turnkey Module, and you told me what it is!
        > THANKS!
        >
        > I found the docs on the 88-CLG modification. This could be a
        problem.
        > All I have is a single 16K RAM board. I guess I have four options:
        > 1) Get three more 16K RAM boards.
        > 2) Build a 64K board.
        > 3) Change something so the stack is located at the 3FFF, or map my
        16K
        > board to reside at C000-FFFF. (is the stack location set by
        firmware?)
        > 4) Undo the modification.
        > I'm thinking that 4) is the best way to go. Any suggestions?
        >
        > I got what I think is an FD 4XX drive, with cabinet and all. The
        > controllers
        > were missing a 7411 and a 7420. That was no problem, once I found
        out
        > what the parts were supposed to be. If a flat ribbon cable will
        work, then
        > I can make one. The construction details are in the documentation
        > that I got on-line.
        >
        > I am just about ready to order some floppies.
        >
        >
        > W. Tom Sanderson wrote:
        >
        > >>I found an 8800bt in a dumpster about 15 years ago
        > >
        > > Congratulations!
        > >
        > >>Replaced the broken front panel switches
        > >
        > > Were you able to find the flat switches?
        > >
        > >> had the lock re-keyed to fit the keys.
        > >
        > > That's good to know. I have several original key types that I can
        > > copy. I didn't know the locks can be changed.
        > >
        > >>Then I replaced all the capacitors in the power supply, even
        though
        > > they didn't seem to have leaked.
        > >
        > > The original one seem to have a long life. Where did you find
        > > replacements? I haven't looked too hard, but haven't had luck in
        > > Albuquerque.
        > >
        > >>Last night I turned it on with no boards, just to test the power
        > > supply. It worked! All three voltages look good.
        > > Did you notice that that there are three options for connecting
        the
        > > transformer? One for <= six boards, one for 7-12 boards, and
        another
        > > for 13-18 boards.
        > >
        > >>The processor board is missing, so I bought one from EBay.
        > >
        > > There are two types. The B models have a newer design.
        > >
        > >> Some of the other boards have missing chips.
        > >
        > > Which ones? The manuals should have parts lists. I can help if
        you
        > > identify the boards.
        > >
        > >
        > >>part that I need right now is a 24-pin wide DIP that goes next to
        the
        > > SENSE switches
        > >
        > > Motorola 6850 UART
        > >
        > > My best guess is that the missing chip has something to do with
        the
        > > serial port.
        > >
        > > Good guess. The port address is switch selectable and must not be
        the
        > > same as a 2SIO board, if you have one.
        > >
        > > The Turnkey Module has been modified. Traces are cut and several
        > > jumpers installed. It looks like the onboard RAM has been
        disabled.
        > > I'm not
        > > sure if this has anything to do with the missing chip, but it
        does not
        > > look like it to me.
        > > 88-CLG modification. See virtualaltair.com turnkey page. RAM is
        > > disabled for business system needing 64K. The modified board
        requires
        > > 64K RAM. The stack is now on the top memory board instead of the
        > > turnkey. After booting, output to sense switch port (FF) and the
        proms
        > > disappear so you have a full 64K RAM.
        > >
        > >>On another note.. Does anyone have any idea how much a Pertec 8"
        > > floppy drive should cost, or where I could get one?
        > >
        > > I have some empty MITS drive cabinets, but haven't decided on
        price.
        > > The dives are a problem. The plastic bezels and doors break easy.
        The
        > > drives are still used in CNC machines and flight simulators. A
        > > refurbished drive may cost $750. The drives are sometimes
        available on
        > > eBay and most people don't know the cost of a bare drive. Ebay
        prices
        > > may be lower than $750 for drive and cabinets. There are several
        > > variations. Two door types for the FD 4XX DC drives (white &
        > > white/Aluminum). Black bezels are FD 5XX AC drives. Single drive
        > > cabinets may be 8800/8800a style or may have an 8800b style face
        > > plate. The 3202 dual drive cabinet has two FD5XX drives.
        > >
        > >>I have the controller cards (with three missing chips), but no
        drive
        > > or cable.
        > >
        > > The controller pairs I have seem to be reliable. Hardware guys
        worry
        > > about some "one-shots". There are two types of cables. The older
        type
        > > has twisted pairs of colored wires. The newest types are flat
        ribbon
        > > cable. Which chips are missing?
        > >
        > >>I'm also looking for someone to copy their software onto floppys
        for
        > > me assuming I can find a floppy drive (I'll provide the
        floppies). Are
        > > there copyright issues with that?
        > >
        > > I have copies of most software. There are copyright issues
        (Microsoft
        > > Software like BASIC or Fortran plus CP/M). I have blank disks too
        > > (32-hard sector).
        > >
        > >>I am having a lot of fun working on this old thing.
        > >
        > > That is how it started. The Altair was a "Hobbyist" computer when
        it
        > > started. Your B model was for "Business Systems" (64K & original
        > > Peachtree accounting).
        > >
        > > Regards,
        > >
        > > Tom Sanderson
        > > www.virtualaltair.com <http://www.virtualaltair.com>
        > >
        > >
        > >
        >
        >
        > --
        > Larry D. Pyeatt, PhD.
        > pyeatt@...
        > http://www.cs.ttu.edu/~pyeatt
        >
      • Larry D. Pyeatt
        Thanks for the info and pointer to the files section of the Altair Computer Club. I didn t know that it was there. It has a lot of stuff that I had not seen.
        Message 3 of 7 , Aug 29, 2006
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          Thanks for the info and pointer to the files section of the Altair
          Computer Club.
          I didn't know that it was there. It has a lot of stuff that I had not seen.

          I compared my Turnkey Board with the 88-SYS CLG mod directions, and I
          am very sure that it has that mod.

          Let's see if I understand how the memory works. I haven't looked at
          the schematics
          yet, but by possibly incorrect deduction, I arrived at the following.
          Assuming a factory
          Turnkey board, without the 88-SYS CLG mod, then the memory map in
          an 8800BT would be:

          0000-03FF PROM provided by the Turnkey Board
          (Writing to Port FF makes this disappear, allowing
          access to
          1K more RAM)
          0000-3FFF 16MCS RAM board (overlaps with Phantom PROM)
          4000-7FFF 16MCS RAM board (if present)
          8000-BFFF 16MCS RAM board (if present)
          C000-CFFF 4MCS RAM board (if present)
          D000-DFFF 4MCS RAM board (if present)
          E000-EFFF 4MCS RAM board (if present)
          F000-F3FF 1MCS RAM board (if present)
          F400-F7FF 1MCS RAM board (if present)
          F800-FBFF 1MCS RAM board (if present)
          FC00-FFFF RAM provided by the Turnkey Board. This RAM conflicts with
          any other RAM mapped into these locations, because
          accessing
          it does not generate the PHANTOM signal. The Stack
          resides here.

          The above takes 9 slots, just for RAM, and costs a LOT. So, the 88-SYS
          CLG disables
          the RAM provided by the Turnkey Board, allowing four 16MCS RAM boards:

          0000-03FF PROM provided by the Turnkey Board
          (Writing to Port FF makes this disappear, allowing
          access to
          1K more RAM)
          0000-3FFF 16MCS RAM board (overlaps with Phantom PROM)
          4000-7FFF 16MCS RAM board (if present)
          8000-BFFF 16MCS RAM board (if present)
          C000-FFFF 16MCS RAM board (MUST BE PRESENT, because the stack
          starts at FFFF and grows down. Can be smaller than 16K.
          RAM on Turnkey Board must be disabled to prevent smoke.)

          With the 88-SYS CLG, the memory board at the top of memory can be
          smaller than 16K. It only needs to be big enough to hold the stack.

          Did I get it right?

          I would like to be able to run Disk BASIC, so I am considering just
          building a
          64K RAM board, using newer technology. Basically, just the voltage
          regulator,
          an 8 by 64K RAM chip, and a few gates. That may be a lot easier and cheaper
          than finding three more 16MCS boards.

          I'm fairly certain that I got the FD400 drive. Maybe I can find a bare
          FD500 and
          swap the drive hardware. What type of disks should I buy?

          Thanks again, Steve. You have been a great help!


          Steve wrote:

          > Larry,
          >
          > For further information on Altair's front panel switches, and for
          > possible sources, look in the FILES folder, at
          > FILES > STEVE'S FILES > 'Sources for 8800b toggle switches.pdf' .
          >
          > A Turnkey board that has the System Kludge (88-SYS CLG) mod installed
          > should work OK with less than 64K, if you have some additional RAM
          > at the top. For example, a 4K board addressed from 60K to 64K. If
          > you can confirm that your board actually has this mod installed
          > (there were a couple of other mods that were similar), then it
          > shouldn't be too hard to un-mod it. If you need a better copy of the
          > instruction sheet than what Tom has posted, I'll upload a bigger one
          > to our FILES folder. Andy Kessel may have some suggestions too.
          >
          > If you plan to use Altair Disk BASIC, I think you'll need at least
          > 32K of RAM for the early versions and 48K for later versions.
          >
          > Pertecs FD400 drives usually had a white front door and used a
          > stepper motor to spin the disk. The FD500s had black doors and a
          > 115VAC spindle motor , which was much more reliable. If the 400's
          > stepper stalled, the TIP driver transistors would usually smoke if
          > power wasn't quickly removed by opening the door. Other than the
          > spindle motors, the drives were interchangeable.
          >
          > Steve
          > ===============================
          >

          --
          Larry D. Pyeatt, PhD.
          pyeatt@...
          http://www.cs.ttu.edu/~pyeatt
        • Steve
          Your description of the sys clg looks right to me. By the way, MITS also made a turnkey board with no RAM on board, for its fully loaded business systems.
          Message 4 of 7 , Aug 29, 2006
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            Your description of the sys clg looks right to me. By the way, MITS
            also made a turnkey board with no RAM on board, for its fully loaded
            business systems. They came out shortly before MITS' doors closed.

            The Altair disk systems used hard sectoring, so you need 32-sector
            diskettes. Check the message archives- I think someone in this group
            had some for sale a while back. The 5" drives required 16 sectors.
            All Icom systems (8" and 5") were soft-sectored.

            Sometimes you can buy non-MITS memory boards pretty cheaply on ebay.
            That may be the easiest way to add more RAM. Godbout, Morrow, SDS,
            and many others made a 64K board. Bear in mind that Altair 500-C
            BASIC running the hard disk accounting packages didn't require a full
            64K, and 48K was enough to run Wordstar.

            Steve
            =================================

            --- In altaircomputerclub@yahoogroups.com, "Larry D. Pyeatt"
            <pyeatt@...> wrote:
            >
            >
            > Thanks for the info and pointer to the files section of the Altair
            > Computer Club.
            > I didn't know that it was there. It has a lot of stuff that I had
            not seen.
            >
            > I compared my Turnkey Board with the 88-SYS CLG mod directions, and
            I
            > am very sure that it has that mod.
            >
            > Let's see if I understand how the memory works. I haven't looked
            at
            > the schematics
            > yet, but by possibly incorrect deduction, I arrived at the
            following.
            > Assuming a factory
            > Turnkey board, without the 88-SYS CLG mod, then the memory map in
            > an 8800BT would be:
            >
            > 0000-03FF PROM provided by the Turnkey Board
            > (Writing to Port FF makes this disappear,
            allowing
            > access to
            > 1K more RAM)
            > 0000-3FFF 16MCS RAM board (overlaps with Phantom PROM)
            > 4000-7FFF 16MCS RAM board (if present)
            > 8000-BFFF 16MCS RAM board (if present)
            > C000-CFFF 4MCS RAM board (if present)
            > D000-DFFF 4MCS RAM board (if present)
            > E000-EFFF 4MCS RAM board (if present)
            > F000-F3FF 1MCS RAM board (if present)
            > F400-F7FF 1MCS RAM board (if present)
            > F800-FBFF 1MCS RAM board (if present)
            > FC00-FFFF RAM provided by the Turnkey Board. This RAM conflicts
            with
            > any other RAM mapped into these locations,
            because
            > accessing
            > it does not generate the PHANTOM signal. The
            Stack
            > resides here.
            >
            > The above takes 9 slots, just for RAM, and costs a LOT. So, the 88-
            SYS
            > CLG disables
            > the RAM provided by the Turnkey Board, allowing four 16MCS RAM
            boards:
            >
            > 0000-03FF PROM provided by the Turnkey Board
            > (Writing to Port FF makes this disappear,
            allowing
            > access to
            > 1K more RAM)
            > 0000-3FFF 16MCS RAM board (overlaps with Phantom PROM)
            > 4000-7FFF 16MCS RAM board (if present)
            > 8000-BFFF 16MCS RAM board (if present)
            > C000-FFFF 16MCS RAM board (MUST BE PRESENT, because the stack
            > starts at FFFF and grows down. Can be smaller
            than 16K.
            > RAM on Turnkey Board must be disabled to prevent
            smoke.)
            >
            > With the 88-SYS CLG, the memory board at the top of memory can be
            > smaller than 16K. It only needs to be big enough to hold the
            stack.
            >
            > Did I get it right?
            >
            > I would like to be able to run Disk BASIC, so I am considering just
            > building a
            > 64K RAM board, using newer technology. Basically, just the voltage
            > regulator,
            > an 8 by 64K RAM chip, and a few gates. That may be a lot easier
            and cheaper
            > than finding three more 16MCS boards.
            >
            > I'm fairly certain that I got the FD400 drive. Maybe I can find a
            bare
            > FD500 and
            > swap the drive hardware. What type of disks should I buy?
            >
            > Thanks again, Steve. You have been a great help!
            >
            >
            > Steve wrote:
            >
            > > Larry,
            > >
            > > For further information on Altair's front panel switches, and for
            > > possible sources, look in the FILES folder, at
            > > FILES > STEVE'S FILES > 'Sources for 8800b toggle switches.pdf' .
            > >
            > > A Turnkey board that has the System Kludge (88-SYS CLG) mod
            installed
            > > should work OK with less than 64K, if you have some additional RAM
            > > at the top. For example, a 4K board addressed from 60K to 64K. If
            > > you can confirm that your board actually has this mod installed
            > > (there were a couple of other mods that were similar), then it
            > > shouldn't be too hard to un-mod it. If you need a better copy of
            the
            > > instruction sheet than what Tom has posted, I'll upload a bigger
            one
            > > to our FILES folder. Andy Kessel may have some suggestions too.
            > >
            > > If you plan to use Altair Disk BASIC, I think you'll need at least
            > > 32K of RAM for the early versions and 48K for later versions.
            > >
            > > Pertecs FD400 drives usually had a white front door and used a
            > > stepper motor to spin the disk. The FD500s had black doors and a
            > > 115VAC spindle motor , which was much more reliable. If the 400's
            > > stepper stalled, the TIP driver transistors would usually smoke if
            > > power wasn't quickly removed by opening the door. Other than the
            > > spindle motors, the drives were interchangeable.
            > >
            > > Steve
            > > ===============================
            > >
            >
            > --
            > Larry D. Pyeatt, PhD.
            > pyeatt@...
            > http://www.cs.ttu.edu/~pyeatt
            >
          • mfeberhard
            Steve, Is the 88-SYS CLG mod documentation posted online? If so, where? If not, can you post it here, in the files section someplace? Thanks! Martin E.
            Message 5 of 7 , Aug 11, 2014
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              Steve,

              Is the 88-SYS CLG mod documentation posted online? If so, where? If not, can you post it here, in the files section someplace?

              Thanks!

              Martin E.
            • wtsnet
              virtualaltair.com Anything Altair http://www.virtualaltair.com/virtualaltair.com/vac_altair_turnkey_module.asp
              Message 6 of 7 , Aug 11, 2014
              • 0 Attachment
                virtualaltair.com Anything Altair

                 

              • alltare
                I just uploaded 88-SYS CLG for TURMON board.jpg to FILES STEVE S FILES. It s the same document that Tom has posted on his site
                Message 7 of 7 , Aug 12, 2014
                • 0 Attachment
                  I just uploaded "88-SYS CLG for TURMON board.jpg" to FILES > STEVE'S FILES.  It's the same document that Tom has posted on his site (virtualaltair.com).Steve===================
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