The Entrepo WaferDrive was released in fall 1984 and at the time it was released in the intention to be a direct replacement for the Vic-20 and Commodore 64 Cassette Deck. It offered load speeds of 10x faster Cassette drives and 3x faster the 1541 disk drive. The Drawback of this little drive was that it could only save your own programs from cassette and 1541 disk drive, and QOS used memory locations C000 to D000 which most programmers used as their default memory. It’s DOS called QOS was easy to use and very little memory was taken from the C64 or Vic-20. The first production drives came in 3 versions which one of them had a cartridge for its QOS, and solved the problem of memory locations C000, but later to reduce the costs the cartridge version was omitted. The media used where called Microwafers and they looked like tiny cartridges. Inside the cartridge there was a looped tape similar to the 8mm track tapes used in the 70’s for audio, joining and marking the beginning and the end of the loop, there was a very small part of the tape coated in silver, which produced a high pitch tone when the tape head passed over it marking the end of the tape.
The Microwafer had to be formatted in order to be used, and when formatted a directory was created so program names had to be unique on the drive. When you delete a program from the Microwafer it was not completely removed but just the name in the directory was deleted leaving the program on the Microwafer hidden from the user. You can tell that the program was still resident on the Microwafer by the size of used bytes in the directory. This was a problem for most users as that space was not available anymore and to regain access to that space, one had to reformat the Microwafer again. There was no workaround for Entrepo for this as the programs where saved one after each other just the same as multiple programs on a cassette tape. The drive had two speeds; the fast speed was to fast forward the Microwafer to the beginning of the tape, which in turn the head had to sense the silver tape, and fetching of the program using the gaps between each program save. The other speed was used to load the programs. The Microwafer came in variety of sizes, 16k, 32k, 64k and 128k. There were the 196K but they tended to break easily and the speed was reduced drastically due to the drive fetching the beginning of the tape and programs. The best Microwafer was considered the 32k as you still have decent speed and fetching of programs in 3 to 5 seconds. Commercial programs were also available but very little software was released in this format as the drive was not a great hit.
The initial price tag at the time was £89 but later sold for £60, compared to the 1541 with a price tag of £240 it was cheap but software houses were very skeptical about the Microwafer tape and said that it can break easily, and were afraid of ending up with a pile of Microwafers returned by their clients. This was also the concern of most users who bought the drive, which pushed other potential buyers not to buy it at all and made the drive not to sell.
Today the drive is very requested by collectors not to use it but just to own it. It’s true that the Microwafer tape breaks inside, but this happens because the tape inside is more than 20 years old and the adhesive used to bound both ends of the tape to the silver strip has deteriorated. 99% of the time the tape snaps from the silver marker while passing the head in the drive. There is a way to fix this the Microwafer which we did it quite a few times to fix them. Using silver contact tape and by replacing the silver part of the tape it worked perfectly. Our drives are used quite often and have no problems at all. There is another method by joining the silver part to the other end with nail polish and leave it to dry for 48 Hrs. The difficult part in both methods is to pass the tape back to its original position inside the cartridge, but if the silver tape is damaged you need to use the first method or the drive will not detect where is the start and end of the tape and keeps spinning in the drive until the timeout triggers that there is a problem with the Microwafer.