a design of Dutch origin
From Holland information reached us that the test stage of the Chipdisk
is closed and that the possibilities for commercial applications are
being viewed. What are the advantages of this really revolutionary
design with respect to existing equivalents such as e.g. the RAMDISK or
the Winchester drive?
To give some clearness about this a description of the system is
necessary. The whole system consists of 4 parts of which a simple but
amply measured 5 Volt power supply forms a part.
The following part is a number of 64 K-dynamic RAM boards connected to
a eurobus. In this approach lies the flexibility of the system and a
basic system only needs such a board. With an increasing need the
Chipdisk can grow along in little steps from 64K to 1/2 Megabyte and
with small adjustments even greater capacities are possible.
part of the design is an interface- board which buffers the eurobus
signals and at the same time generates a number of extra control
signals. The part discussed until now is assembled in a case and has
the appearance of a diskdrive, entirely complete with power-on led and
activity led. This case is connected by means of a 50 way flatcable
with an I/O board in the host computer on which the processor signals
are buffered and three I/O ports are decoded. The whole system gives
the host computer only a load of three I/O ports, Through this the
Chipdisk can in principle be used on every
8088 system and in the future adaption for other processors is probably
The system which is finished now, has been designed for
the Nascom Gemini 80 bus and it operates with 128K ram to great
satisfaction. By making a clever use of modern IC’s the software
interfacing is extremely simple and the Chipdisk reacts like a normal
floppy disk drive with sectors of 128 bytes and tracks of 16 sectors.
The number of tracks
is dependent on the number of RAM boards and amounts to a multiple of 32.
The interfacing is extremely simple and for
is available while for other applications flow diagrams are available.
After this description of the system I shall now mention a number of
advantages with regard to the systems mentioned before. The RAMDISK
such as many systems apply it. constitutes the system memory and is
then addressed in page mode or via banking. These are often costly
provisions which make a system for non-users of it unnecessarily
expensive. The software for this is also very complicated and
everything is system bound. Another possibility are instant I/O boards
for a particular bussystem with certain great quantities of memory
which are also systembound and often cost a great amount of money.
The advantage of the chipdisk is in this case the modular buildup so
that one can start with a small and relatively cheap system. In
comparison to the Winchester which couples great storage to high speed
the Chipdisk is as regards the price per bit disadvantageous but the
great vulnerability and the high purchase price of the Winchester drive
are the reverse side of the medal. The hard- and software interfacing
is much more complex too.
In the way of speed the Chipdisk is in all cases amply the winner and a
speed gain with a factor 30 is with respects to a floppy no exception.
I do not wish to conceal a disadvantage of the Chipdisk either. It is
clear that when the computer is switched off the data in the Chipdisk
get lost, so that the results of an operation as the last stage must
always be written to a real floppy.
The application of the Chipdisk
therefore lies mainly in the realm of sorting, assembling, compiling
and designing operating systems.
For further information about this new medium please you can apply to
the designers of the Chipdisk.
H. Vermeulen,H. Rietveld