80-Bus News


January–March 1982, Volume 1, Issue 1

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Edit and Ecmd   These overlay files control the EDIT command, enabling seperate source and destination files to be given as parameters. The editor supports a wide range of functions and acts as a window on the text. Commands are available for moving/​inserting/​deleting/​finding-changing portions of text in a most powerful way. The files created are suitable for submitting to the assembler or BASIC or as just text files. The Edit overlay may also be called by a user’s program for specialised applications. A seperate utility program is available called Polytext for formatting and print time adjustment of letters and documents.

FORMAT The format utility programmme is used for the first time initialisation of blank diskettes. It allows disks to be formatted in single density or double density in the case of a G815/G809 system with automatic verify to check the data can be read back. Diskettes may also just be verified if required.

BACKUP This utility program is used to make direct image copies of diskettes as the name implies, it can also be used on a single drive system allowing the user to place the source disk in the drive which is then read, the user is then prompted to place the destination disk in the drive and the data is then transferred.

SZAP This very powerful program allows you to dive straight into the disk and display the data held there. This is not for the faint hearted since the data can be directly modified on the disk, thus a few careless key presses could result in loss of directory information and render the data useless.

When “BASIC” is typed in the command line mode, a file called “BSdr.BR” is loaded which holds the routines for the Disk BASIC, control is then passed to the ROM BASIC. The BASIC under Polydos is an enhanced version of the Nascom BASIC allowing such features as:

Direct mode commands.

LOADLoad a BASIC program file from disk
SAVESave a BASIC file to the disk in memory image format
SAVETSave a BASIC file in ASCII text format
EXECLoad and RUN a BASIC program file
AUTOAutomatic line numbering
RENLine renumbering
FINDFind a string

Program/​direct mode commands.

SETNEWOpen disk data file, random or sequential access are available
SETINPInput data from a disk file
SETOUTOutput data to a disk file
SETPOSSet file position pointer in random access mode
SETCLSClose a disk file
SETLOADLoad a file into memory (typically machine code subroutines)
SETCHAINLoad and RUN a BASIC program and leave variables untouched
SETPRONEcho output to the printer
SETPROFFTurn off the above option
SETERRTrap program errors
SETREADInput string variable with editing facilites
SETCLEARDefine string space and memory size
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