| hardware world |
QSAVE fast loader hardware |
THE MOST exciting product being reviewed this month is QSAVE by PSS. It is a hardware and software package which will allow you to save and load tapes at 16 times the speed of Sinclair ROM commands.
The hardware consists of a small black box which plugs into the ZX-81 EAR and power sockets via two 3.5mm. cables. The power supply and EAR lead from the tape recorder are plugged into two 3.5mm. sockets on the other side of the box which contains an amplifier and two filters which eliminate any noise produced by the tape recorder. It also cleans the signal which has been recorded and can be used on its own to improve the loading of machine code or Basic tapes.
The software does the tricky bit and has to be LOADed first in the normal way before QSAVE can be used. It Auto-Runs and transfers a 300-odd-byte machine code program above RAMTOP. There it will stay unless you remove the power or use the NEW command. PSS will provide a tape for use with any memory size.
Three routines are provided via PRINT USR X where X is the routine required. They are SAVE, VERIFY and LOAD. They will enable you after you have LOADed a Basic program in the normal way to re-record it in QSAVE format - 16K takes 30 seconds.
After re-winding the tape it may then be verified and checked against what is stored in memory. LOADing of any program QSAVEd must be done by the LOADing routine provided. As it takes only 30 seconds to LOAD a program of up to 16K that does not take long; if the VERIFY command does not recognise the QSAVE program it will not return to Basic, so the only way to get out of it is to load known loadable tape.
That is its major failing but PSS says it will be corrected by now.
The price is £15.95 inc. VAT and postage-64K version £17.95. A version with a switch prevents you having to pull out the EAR lead of the cassette recorder when SAVEing. PSS is at Coventry.
A CMOS battery-backed RAM board for the ZX-81 is available as a kit. The board has four sockets which can be used for 2K RAM chips (6116) or 2K and 4K EPROM and by placing the chips in different sockets it can be made compatible with other equipment - graphics ROMs, Toolkits - which inhabit the same 8K-16K space on the memory map.
The kit should take approximately two hours to make, Hunter Electronics says, and the RAM board can be moved to any 8K space in the 0-32K section of memory. It can then be used to modify the Sinclair ROM by replacing it with 8K of RAM which, because it has a lithium battery, does not lose the program when the power is turned off.
The expected life of 2K of RAM using the battery only is 10 months, or two months with a full 8K of RAM. The cost of the kit is £19.95 inc VAT, plus £1.95 for postage. It is supplied with only one 2K of RAM on board. Hunter Electronics is at Axminster, Devon.
RD LABS has made most of its range of input/output ports Spectrum-compatible. So the scientific or educational user has a wide range of test equipment at his disposal. Devices include digital I/O ports, analogue inputs to one port and a real-time clock.
The clock is battery-backed and has a calendar, as well as the time protected for up to four months without power.
All the units are memory-mapped and Spectrum users require an adapter as well as the basic motherboard and ports. The prices range from £33.93 for the digital port to £51.24 for the real-time clock/calendar. The Spectrum adapter costs £9.50 extra.
There is a 10 percent discount for cash with order but you must add £3 postage to the VAT-included price.
RD Labs also does mainframe units for industrial users; price on application to RD Labs, Herts.
ANOTHER hardware/ software combination is from Quicksilva which now supplies keyboard overlays for its Spectrum games-Space Intruders and Meteor Storm. The black pieces of plastic fit over the keys and are really convenient as they tell you in bold letters which is THRUST-ROTATE LEFT and the like - a real incentive for buying the excellent QS games.
QS is at Southampton and the tapes can also be obtained through some micro shops specialising in ZX equipment.
HAVEN HARDWARE no longer offers the ZX-81 colour board due to the lack of a satisfactory modulator but will sell the circuit diagram for £4.95.
Haven sells three other modules. A single-entry key module can be soldered on to the ZX-81 or Spectrum, although the connections are different. It is ideal for those with an external keyboard with a few spare keys on it. It costs £2.95 as a kit and £4.95 made up but not fitted. The beeper is a standard oscillator which operates every time a key is pressed. It costs £8.90 and £7.50 as a kit. The third offering is an inverse video module but it tends to be unstable.
Haven Hardware is at Workington, Cumbria.
DEAN ELECTRONICS, in co-operation with The Buffer Shop, London, has produced a modified version of the ZX-81 keyboard for the Spectrum. It costs £35 and a black case to contain it and the Spectrum PCB will cast £15 inc. VAT.
They can be obtained only from The Buffer Shop and £1 must be added if ordering by mail for postage and packing.
The ZX-81 version has a space bar and a typewriter-style key layout - it is the same keyboard, but Spectrumised.