Updating ROM and memory

MemoryNowadays to talk about Megahertz, Megabytes and even Terabytes for computers is an everyday thing, but thirty years ago computers with 1 MHz and 128 Kilobytes (yes, kilobytes!) were the norm, and updating them were not as easy, specially in portables like the Apple //c.

Reading a bit about its history, I learned that there were several updates not only the motherboard, but the ROM, the first to enter UniDisk then to read extended memory, which could be from 256k up to 1 Megabyte.

Apple offered not only memory cards, Applied Engineering actually created a clock, CP/M and memory card, but today those cards are very hard to find. One of the rarest memory expansions is precisely what Apple offered, and today it’s also really hard to find.

So participating on a retro computer forum, I met someone who had an extra original expansion card for the Apple //c, and I convinced him to sell it to me, in fact at a very good price. At the same time, learned that the ROM version of my motherboard was 3, and there was an update that managed some problems with extended memory.

The problem is that you cannot order these ROMs from Apple any more, and they are not for sale anywhere, at least officially. There is a site that advertise them, Reactive Micro, but apparently they have no longer in existence.

After more research I found the images of the ROMs in a New Zealand site, and used a Canadian company, EPROMPro – to “burn” me the corresponding ROM chip.

It finally arrived, and proceeded to install it fearfully: considering that the ROM comes from a non authorized site, and the person who “burned” the ROM has no way to test it, I’m risking breaking or even disable my valuable computer.


ROM version 4: Memory expansion fix

Replacing the original.

Insertado y listo para probarse.

Inserted and ready to test

The real test: “PRINT PEEK(64447)” and the return number means the version.

Now for the principal piece: the Apple //c memory expansion, brand new!

Tarjeta de expansión con 1 MB Memoria Apple IIc

preparing for the operation

The expansion port under the keyboard

Instalado y listo para la prueba
Installing and all looks fine
Probando la memoria, ¡veinte veces y todo bien!
Testing, everything fine!

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