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I recently received an order from Larken Electronics with Ramdisk on a medium-sized (3×7) circuit card and a replacement EPROM chip for the LKDOS disk controller cartridge.
The chip is an updated version of the disk operating system so that LKDOS can support the Ramdisk.
The Ramdisk board has a feed-thru connector that plugs into the rear expansion buss of the 2068, and 4 empty sockets on the back-side of the card. These sockets hold the ramchips, which must be bought separately. At one edge of the ramdisk board is a battery clip to hold two “AAA” batteries. With batteries installed, the contents of the ramdisk are preserved when the 2068 is turned off or Ramdisk is unplugged.
The LKDOS Ramdisk accepts up to four 32K ram chips without moditication for up to 128K of storage. The board uses 32 x 8K static ram chips (part no 43256L or 62256L). To install memory beyond 128K, four more empty sockets must be soldered ‘piggyback’ to the first four ram chips, but this is relatively simple for anyone who has used a soldering iron.
Once installed, the ram is ‘formatted’ with a single command from basic and ready for use.
The Ramdisk behaves exactly like an ordinary disk drive in LKDOS, only a lot faster. The same commands are used; only where ordinary drives are numbered Zero to Three, the Ramdisk is drive Four. PRINT *4: CAT **• instantly responds with a catalog of the files under a heading “Disk drive name: RAMDISK”. I could even change the Ramdisk drive name with Larry Kenny’s recently released disk editor utility.
AUTOSTART files can be saved to the Ramdisk. Turn the 2068 on while pressing ENTER and the “J” key simultaneously w1l1 boot the AUTOSTART file from ramdisk instead of the regular disk drive.
Screen images loaded from the Ramdisk consecutively appear so quickly that an animation effect is achieved. I found that being able to load, save, boot and re-load files to ramdisk continually instead of disk saves a lot of time and hassle. When I’m done, I dump the contents to a floppy.
This illustrates the Ramdisk’s intended use to speed up existing programs when files are loaded and saved frequently, as opposed to increasing your disk space. Also, a 256K ramdisk stores more than an ordinary single-sided, double-density floppy disk.
The only problem I have encountered so far is some interference between the Ramdisk board and the ‘stock’ ZSIO RS-232 card and modem at 1200 baud. However, l do not know if this is a problem with the Ramdisk, software, the ZSIO, or plain power drain. (As it is, I have 7 devices chained to the back of my 2068). Other than that, I have found the LKDOS Ramdisk to be one of the most versatile tools yet for the 2068. Any serious 2068 user would do well to consider purchasing one.
The LKDOS Ramdisk 15 available from Larken Electronics at RR #2, Navan, Ontario, Canada K4B 1H9 and most local T/S dealers. Ramchips for the Ramdisk are about $14.00 apiece at Jameco (415-592- -8097 ta order). Chip sockets are about 50 each at Radio Shack.