Not all of the software in the Master's 128K ROM appeals to all users. Vine Micros, realising this, have released their Master ROM Overlay Board at a cost of £19.95. This allows paging out of any of the software contained in the 128K ROM, and substitution of your own ROMs. The board comes with good documentation and takes just minutes to fit. After removal of the 128K ROM from its socket in the Master (Beware! Some Masters have their 128K ROM soldered in), the board plugs into the vacated socket, and the 128K ROM is inserted into a socket on the Vine board.

Three further sockets on the board are used for your ROMs, and by means of links, you can page out up to three of the eight ROMs in the Master's 128K ROM.

There are slight problems with this though, as View in the 128K ROM contains some OS code as does Terminal, whilst the DFS contains the SWR routines. This leaves the ADFS, Edit, Basic and ViewSheet as possible candidates for paging out without trouble. I find the board a useful addition to my Master even so.

One way around the lack of ROM sockets on the Master is by the use of cartridges. The Acorn ones are hideously expensive at £14.95, and easily broken when removing ROMs. Peartree Computers have now produced several cartridges of their own for the Master. The cheapest at £5.95 consists of a plug-in PCB with a handle for removal, but no case. This is fine, but does wobble about when in the machine, though this caused no problems in use. Their next offering is a cased version called Pear 1 at £7.95, again allowing the use of two ROMs and worth the extra I feel, for the better fit and protection.

Peartree's MR6000 cartridge costs £9.95, and will accommodate up to four ROMs. Any two ROMs can be active at one time, and are selected by means of a switch on top of the cartridge. A further feature of the cartridge is that it may be used as two 16K banks of SWR by inserting four 8K CMOS RAM chips. The RAM may be loaded like any of the Master's own SWR banks with ROM images, and a switch on the cartridge allows write-protect. At the price, this is a real gem, though one of the units we tested did need a file applying to it before we could plug it in.

Peartree also supply the cartridge with RAM as the MR7200 for £26.95 along with a useful utility disc.

All these products can be recommended without hesitation to those who have a need for the facilities they provide. Construction and design in all cases is good, and the Peartree cartridges in particular, represent excellent value for money.

Product : ROM Overlay Board Supplier: Vine Micros Marshborough, Sandwich, Kent CT13 0PG. Tel. (0304) 812276 Price : £19.95 inc VAT & p&p

Product: ROM Cartridges Supplier: Peartree Computers Ltd, St. George's House, 14 George St, Huntingdon, Cambs PE18 6BD Tel. (0480) 50595 Price : £8.35, £10.65, £12.95. With RAM £33.50.

Three further sockets on the board are used for your ROMs, and by means of links, you can page out up to three of the eight ROMs in the Master's 128K ROM.

There are slight problems with this though, as View in the 128K ROM contains some OS code as does Terminal, whilst the DFS contains the SWR routines. This leaves the ADFS, Edit, Basic and ViewSheet as possible candidates for paging out without trouble. I find the board a useful addition to my Master even so.

One way around the lack of ROM sockets on the Master is by the use of cartridges. The Acorn ones are hideously expensive at £14.95, and easily broken when removing ROMs. Peartree Computers have now produced several cartridges of their own for the Master. The cheapest at £5.95 consists of a plug-in PCB with a handle for removal, but no case. This is fine, but does wobble about when in the machine, though this caused no problems in use. Their next offering is a cased version called Pear 1 at £7.95, again allowing the use of two ROMs and worth the extra I feel, for the better fit and protection.

Peartree's MR6000 cartridge costs £9.95, and will accommodate up to four ROMs. Any two ROMs can be active at one time, and are selected by means of a switch on top of the cartridge. A further feature of the cartridge is that it may be used as two 16K banks of SWR by inserting four 8K CMOS RAM chips. The RAM may be loaded like any of the Master's own SWR banks with ROM images, and a switch on the cartridge allows write-protect. At the price, this is a real gem, though one of the units we tested did need a file applying to it before we could plug it in.

Peartree also supply the cartridge with RAM as the MR7200 for £26.95 along with a useful utility disc.

All these products can be recommended without hesitation to those who have a need for the facilities they provide. Construction and design in all cases is good, and the Peartree cartridges in particular, represent excellent value for money.

Product : ROM Overlay Board
Supplier: Vine Micros Marshborough, Sandwich, Kent CT13 0PG. Tel. (0304) 812276
Price : £19.95 inc VAT & p&p

Product: ROM Cartridges
Supplier: Peartree Computers Ltd, St. George's House, 14 George St, Huntingdon, Cambs PE18 6BD Tel. (0480) 50595
Price : £8.35, £10.65, £12.95. With RAM £33.50.