80-Bus News - September–October 1984, Volume 3, Issue 5

SUMMARY OF GSX OPCODES - continued

Opcode	Description.
28	Input locator. This function serves as the interface between GSX and the outside world. Typically this will call the digitiser or mouse to return information on its whereabouts. When in request mode a cursor will appear on the screen and move according to the action of the specified input device. When in sample mode the current locator position is immediately returned and is often used in conjunction with ESCAPE 18 to plot a graphics cursor while at the same time displaying a rubber banding line.
29	Inquire input valuator. If some sort of analogue device is connected to the workstation, then the current value of its status is returned. Could be of use if graphical displays of external monitoring devices is required.
30	Inquire choice device. The choice device may be something like a keypad or function keys. For use in menu driven applications I would imagine.
31	String device. This returns a string from an input device which will of course be the keyboard in most cases.
32	Set writing mode. This affects the way in which lines or filled areas etc. are placed on the screen. The modes available are replace, overstrike, complement (XOR) and erase.
33	Set input mode. This lets you specify the type of input device you will require next i.e. locator, valuator, choice or string. You have also to specify whether this device is to operate in request or sample mode. In request mode the device waits until an event occurs such as the digitiser pen being pressed down to terminate input, in sample mode the current status or location of the device is returned without waiting.

Private Sales

Micropolis 400K Single/Sided Disk Drive, £85.00. Climax Colour Card and Software, £75.00. Mr Ward, Macclesfield (____) ______.

Large 19″ rack case suitable for Gemini/Nascom with 8-slot card rack, floppy disk mounts, power supply. £85.00 ono. Plus Nascom 2, 64K RAM A card (4 MHz), cased with power supply and earom programmer. Software includes Nas-Sys 3, Zeap, Nas-Pen, Nas-Debug, Tool Kit, Documentation, etc, £220.00 ono and Gemini GM812 IVC card, £120.00 ono. Please make me an offer, I may not be able to refuse it. St Albans (____) _____.

Nascom IMP printer with Imprint operating system, spare ribbon cartridges and various electronics spares in original packing, £110.00. Nascom 1 with genuine Nascom 2 keyboard and PSU card, £60.00. Bits & PCs hexadecimal and control key-pad kit, £12.00. Gemini GM804 5v/12v PSU for twin disk drives, £15.00. Twin 19″ matching instrument cases, to accommodate 5-card rack and PSU, and 2 standard height disk drives with PSU, £20.00. Carriage at cost. Telephone (____) ______.

IBM Selectric KBD Printer, ex 2741, with Hardware/Software interface for Nascom 2/Nas-Sys or any system with 8-bit port/Z80. In excellent working order, with Service Manuals. Haggle around £115.00, Ian on Ipswich (____) ______. (PS Faster than some cheap daisy wheels, and better print Q.)