£24.00 (£28.80 inc VAT)

Apple II ProDOS bootable 1MB read-only drive
[ProDOS ROM Drive] - Stock: 9

The ProDOS ROM card will allow an Apple II and variations to fast boot into a fully functional ProDOS install without requiring a floppy drive. It achieves that in under two seconds with no wear and tear. Contents of the ROM card are permanent and read only so the programs are always available.

The ProDOS ROM card is preprogrammed with ProDOS, the serial/audio/Ethernet ADTPro client and an example selection of games and utilities. CiderPress or another utility supporting the Apple ProDOS filesystem can be used with a blank ROM image to create your own custom software selection. We have programmed the EPROM to be bootable on both v2.5 and v4.0 units.

CiderPress or another utility supporting the Apple ProDOS filesystem can be used with the blank ROM image to create your own custom software selection.

An optional ZIF (Zero Insertion Force) socket, instead of turned-pin, is available for easy reloading of EPROM. Please note that due to the height of the ZIF, it makes the card slightly thicker and might cause space issue with the adjacent card. We tend to use Slot 7 as there are plenty of space in the Apple II for EPROM changing operations.

Below is an example of the structure of the EPROM.

PRODOSSYS
BITSY.BOOTSYS
QUIT.SYSTEMSYS
BASIC.SYSTEMSYS
GAMESDIR
ADTPRO.2.1.0DIR
UTILSDIR

The supplied EPROM is a 27C801 UV erasable device. A suitable UV EPROM eraser and an EPROM programmer, such as the Minipro TL866, will be required to reprogram the EPROM. Care should be taken when removing and inserting the 32-pin EPROM. Please note that only ProDOS compatible programs may be run with this particular firmware implementation. Apple DOS programs cannot be used unless the program is amended appropriately. Full firmware source code is available from the designer's GitHub page below.

This expansion card may be used in any of the Apple II expansion slot and will be the first to boot regardless of any disk controller present. To boot from a normal disk controller, please select BASIC.SYSTEM to exit to ProDOS and type PR#6 to boot from that device as per normal.

ProDOS ROM Drive v2.5 design and firmware by Terence J. Boldt.

Please note that version 4.0 is mostly a small relocatable code saving of less than 20kB, hardly a significant amount when set against the 1MB available. It also corrects a minor design oversight that didn't properly buffer the data bus but that seem to have no adverse effect on the operation of the ROM drive. The PCB has a very minor change but with the same ICs as v2.5. The units we will supply are now all v4.0, although there is no noticeable difference between the two apart from a very small difference in the EPROM memory.

If you have purchased v2.5 from us and wished to have v4.0, please return the unit to us for upgrading to v4.0. We will transfer the ICs from the returned unit to the v4.0 PCB and the old PCB recycled. We only charge for the cost of the return postage as part of our service to our customers.

  • Apple II expansion slot compatible
  • ROM size: 1MB
  • ProDOS size: 2044 blocks (1022kB)
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