INMC News

  

Autumn 1979, Issue 4











Page 12 of 30











10     PRINT “8K BASIC PAGE”

Not too much about the 8K BASIC at this stage as there aren’t many about yet, although with Nascom 2 just round the corner, there’ll be plenty more soon.

Let’s clear up some questions; the BASIC is compatible with both NAS-SYS and NASBUG T4 (it also works with T2, but you lose ‘CSAVE’), and when you execute it, it’s clever enough to sort out which monitor is in use. The main difference between the behaviour of the BASIC under NAS-SYS and NASBUG is the loss of the ‘on screen’ editing facilities under the latter. The 8K BASIC will finally be supplied in an 8K by 8 mask programmed ROM of the MK36000 series, and called “Nascom ROM Basic”. Now this is a good choice of chip, as the legs are almost 2708 compatible. Where do the extra 3 address lines go, you ask? Well as the chip only needs a single +5 volt supply, two pins on the 2708 present themselves as obvious choices, and as you don’t program ROMs, the program pin is the other. All this means that it shouldn’t be difficult to adapt a Nascom series 1 memory card to take the ROM (at the expense of the EPROM sockets), and in theory, only three knife cuts and three wire links need to be added to the board to make it work. That’s theory of course, we’ll have to wait till we get our paws on one to prove it!

Now we have heard of one dealer who has a tape of the ROM (it seems that all dealers were supplied with EPROM versions of the ROM sometime ago) and is offering copy tapes with interim documentation at about £:45.00. What he says is that by paying now and taking the tape, you have paid for the ROM when it arrives, and of course have preference when his supplies of the ROM arrive. He also says he will charge or return any balances if the price of the ROM is different when it arrives.

This doesn’t sound a bad idea for those who are that desparate for the BASIC, but of course there has to be a snag. The BASIC is designed to run in memory from #E000 to #FFFF and requires text space from #1900 onwards. This means that your memory has to be split into two halves, one at least of 8K contiguous memory, which in turn has to be located so that it will work from #E000 to #FFFF. That means you’ve got to invest in two 8K boards or have 32K of RAM on one board. Owners of 16K on one board (and from the sales thats the majority) don’t get a look in.

So up gallop Nascom, to the rescue on their white charger, but like a lot of gallant forays of this nature it may be a mixed blessing. Nascom have re-assembled the BASIC to run from #1000 to #2FFF with text space starting at #3000, they call this “Nascom Tape Basic” (‘CSAVE’ works under T2 as well). The problem is that although the two BASICs are identical (in the way they work), tapes of programs generated using the ‘CSAVE’ command are not. The two versions of BASIC use different text space areas, and as ‘CSAVE’ calls ‘Write’ in NASBUG/NAS-SYS (or ‘Dump’ in T2) to output the data, then on ‘CLOAD’ the data will be reloaded to the wrong place (if at all) if not used with the same


This is an OCR’d version of the scanned page and likely contains recognition errors.











Page 12 of 30