RAM Floppies are memory-wide conditions that simulate a second drive-only is written directly into RAM at high-speed, not on a floppy disk. We have tested the Rex-RAM-Floppy for you.

Who uses his Commodore 64 for word processing or data management, has requested certainly need a larger memory. 64 KBytes are a lot, but not always enough. Rex offers a board. the memory of the C 64 extended by up to 256 KBytes.

This "RAM-Floppy" looks quite inconspicuous at first glance: the mid-sized board contains various passive components as well as a 2764-EPROM with the operating Software. a Reset button, an on/off switch and an operating indicator. The positive is that all ICs are docked. Unfortunately, the relatively stable-looking Board was equipped with no housing.

The buyer decides how much additional RAM he wants to provide his C 64: He uses the memory to expand, simply in addition to the two already supplied with the RAM-Chips new type 6264 or 4364 (8 KByte), or 43256 (32 KB) to the eight sockets on the Board. This is available for a few Mark to buy in specialized stores. The RAM-Floppy automatically recognizes the expansion stage when it is switched on.

The Board is simply plugged into the Expansion Port. If you turn on the Computer, the Hardware is already active: The control software Is contained in an EPROM. This has the advantage that you do not have to load from floppy. In addition, almost no memory in the C 64 is used. Manipulations are of course complicated.

The additional memory is addressed like a new diskette station with the device address 7. This is an advantage, for example, over the RAM expansion of Commodore, which is not so easy to use. Up to 100 programs can be stored on the device address 7. However, the device address can be changed via a POKE command.

The operation is also not difficult for beginners, because errors (e.g. "RAM Disk full" or "Name already exists") are displayed immediately. The memory extension even creates a Directory that can be called on when needed.

Also otherwise the board is quite compatible to Floppy 1541: you can not only save programs and load them again. In addition to the Directory function, there is also the possibility to create sequential files. Also the command channel 15 was thought of: you can format the RAM Floppy, delete or rename programs. This allows existing programs to be adapted to the RAM Disk. However, the evaluation of the command channel is quite "pungent": if you send a faulty command, the RAM Disk reacts uncontrolled. An error message does not appear.

Especially interesting is the possibility of battery buffering: connecting two 1.5-Volt batteries to the board, they are charged with the C 64 switched on and supply" overnight " the RAM Chips with electricity, so that no program is lost when the C 64 is switched off. If necessary, batteries are enough, but this has a small hook: when (as it is stated in the manual) "first turn on", the RAM Disk initializes automatically. This means that all programs are deleted. Unfortunately, the-first - power-on detection does not seem to work 100%: during the test, it occurred that the initialization took place after the start of the test, although the RAM-Floppy was previously activated and still contained programs due to the battery buffering. These were of course deleted.

What about compatibility with commercially available Software? If you switch it off with the switch on the board, the RAM-Floppy can remain in the Expansion Port.

Great, but slow

Because it is then separated electronically from the C-64, running virtually all programs. The situation is different when the extension is turned on. Here, about half of all professional programs, especially games, is not correct. This is because the operating software still uses some bytes, for example, in the processor stack, and changes the kernal vectors. But as I said: In such a case, you can turn off the RAM Disk. However, a little more compatibility would certainly be desirable.

From a RAM Disk it is expected that it not only provides a large memory, but also the transfer of programs to the RAM is carried out quickly. The Rex-RAM-Disk is certainly not one of the fastest: about five seconds are needed to store a 202 Block (51 KByte) long program. If you add this to the maximum memory of 512 KByte (we were standing for the Test unfortunately only a previous version with 64 KByte for presentation) you get to about 50 seconds to fill this memory. This is a great deal, given that the data transfer is going on in parallel.

Bottom line

This RAM Disk is an interesting purchase for C 64 users who, for whatever reason, urgently need more memory. You can test programs that perform many simple floppy disk access with the extension. Although not as fast as it might be, it is still significantly faster than a 1541 drive. Professional users, who certainly would have the most from the RAM Floppy, have to write themselves programs for this, however, because so far there are no Text or data management programs that work with the new storage medium. But that can still happen. Perhaps the manufacturer also decides to release a new version of the RAM Floppy, where the smaller weaknesses are eliminated. It would be a nice thing if you had some programs available after switching on the C 64...

(Nikolaus Heusler / ap)

64'er rating: Rex-RAM-Floppy

Summary

The RAM-Floppy extends the RAM memory of the C 64 by up to 256 KByte. The user can freely choose the configuration level in 8 or 32 KByte steps. The memory is addressed like another 1541 drive. It is especially suitable for professional users, as soon as the smaller weaknesses and programs are written for it.

Positive

. Memory capacity free selectable

. is addressed as a drive

. fully switchable

. Directory, and command channel

. all Chips socketed

. good board quality

Negative

. Initialization does not work properly

. not very compatible

. no special Software available

. no housing

. not very fast

. high price

Contact and info

Product: Rex-RAM-Floppy "9680" , version V3. 3

Tested configuration: C 64. VC 1541, MPS 803, various Software

Prices: 99.95 Mark (Blank): 18995 Mark (64 KByte Version); 4995 Mark (32 KByte Extension Set)

Manufacturer: Rex Datentechnik, A. König, Weidestr. 18, 5800 Hagen 1,

Phone 02331/335092

Provider: Specialist Retailers

Computer translated of the German original article, published in:
64'er
Issue 9 / September 1988
pp.166-167

ref: https://archive.org/details/64er_1988_09/page/n165

Nikolaus Heusler
01.09.1988

Keywords: C64, Commodore, Hardware, RAM Expansion, RAMdisk