Scor­pio News


April–June 1987, Volume 1, Issue 2

Page 26 of 51

The above example may appear trivial, but the concept can be extremely useful in

Error Handling, or conerolling the flow of 4 command chain. “The feature is not sential to the successful operation of the @ system however, and aay be

omitted to save the sk it occupies, if memory conservation Ls important.

‘The Input/Output Segment.

this segment is optional, and its size 4 dependent on what facilities the user hae included. In the memory map Fig-t, it ty shown as being 1 3x bytes Long Since this segment is hardware specific, it becomer the responsibility of the user to weite this software, An example source file for an IOP is provided, to show how it may be done Since I have only one Screen and Printer, and have no

‘available in the IOP, 1 have not implemented this ory is Lost to it on my syster ‘The purpose of the TOP is to provide more flexible control of system T/0 and to

‘low redirection and eo on Tt becomes easy to aviteh to different terminals and printers. If {v is implemented, it can ro » large extent replace BIOs I/O, fod this could result in # smaller BIOS, offsetting the extra memory needed by the OP

The Wheel Byte.

The purpose of this Byte has been described shove. It is Just a one byte location, allocated somewhere in memory, In 22, address OOSBH was used In 23, the author has switched to OOM3H in the documentation, but has aot explained the reason for the move. Since this would restrict the External Fath length, 1 have Tete che Byte at COIBH The byte may be examined, set OF reset ae described above, and 4 orility to manipclate it is alse provided,

‘The Maternal Path

‘The path may be made internal to the CCP, but would then disappear when progr are loaded, The author chose fo use locations from 000M in beth 22 and’ 23y this Seems reasonable The path Tong ag one Likes, hue is in reality Festricted by the memory space available for it from 0040H, and the fact that the longer it is, the longer a search takes, especially when one has type ‘dud’ Cite name. “23 can be eesembled to minimize the path so chat Locations that appear more than ence are only searched once. The current drive and weer are ALWAYS searched first anyway, s0 do not appear in the path. on ay system T Currently search up to seven locations after the current DU. They are:

$0 00, – A15, = AS, = BO, – B5, – CO where SaCurrent Drive or User bearing in mind that A:, Br are the two pacts of a Winchester, C1, D: are Floppies the free memory of the TCAP could be weed for the Pach and Wheel ayte

ZOpRa uesiiti

There are too many 23 utilities to describe more then a few in any detail. ALL of them are designed to work with 23, although some Will run on standard OP/M. Many of them read the ENV segment and make use of the screen facilities defined thece, cesulting in an improved display,

Many also make use of the various buffere and stacks described above

In other words 23 and its command utilities are an integrated Together thoy fore remarkable systes, 23 without its utilities ty still good Many of che 23 utilities will not work on a non-23 system. They fail into several natura! groups, depending on the function,

Copying –

MCOPY is appropriate when multiple copies or complex stcings of commands are Fequiced. ‘Ie copies files from any DIR/DU to any other (Including users between 1e"and 21), verifying the copy and reporting erfore. Te will perfora multiple

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

Page 26 of 51