Scor­pio News

  

July–September 1987, Volume 1, Issue 3











Page 27 of 67











During installation of 23 on ana friend’s Alphatronic PC, some very peculiar errors aro 2 ‘ing been Loaded oF

rubbish. The data found there by the 23 CCP ‘the NDE

Segment, and select errors w

prominent anonge!

‘The inetallation notes buffer aves in turn. the code required {s virtually repeat Simpler and does not take much Longer te cle Initialiestion of startup commands, paths etc, can then follow. the total amount of code needed Zor cold boot patches, and could eimplify Installation where BIOS source ie not avaliable.

ed method of system initialization in the Cold Boot routines is to vr buffers and segment areas, initialize the path, wheel byte, and startup commands, print signon

che supplied utility LDR.COH to load the required on a floppy sd system, there does not usually appear to be much alternative to this method of booting due to space limitations on the aysten tracks of the diek, but Ef one has aparevepece on the floppy system track, or # Winchester, there is 8 etter way.

If two tracks are avallable.. after lable ‘for the BIOS

‘A track on a Winchester disk may be 8k – 6.5k byt: Feserved for the system, thea about 16 – i7k of subtracting BDOS, CCP and Cold Boot Loader, snd 25 sequence! end buffers, and 3108 workepac that the 23 ons can be considered to be part of the system, and loaded with the ‘Cold boot. Since the buffers can be opeionaliy Load tfacks as woll, already initialized to zeroes, or with eet ate, the amount of cold boot initialization becomes minimal, with only the Gefault path and wheel byte needing setting up, although these could be defined somewhere in the Z3 memory aren and loaded with the system too. This Nas the Earcher advantage chat no S105 modifications are needed, except in the sere Edit routine Te then also becomes Unlecessary to use LORCOM, except to change the default segmonte for spectal purposes.

If this approach ie used, but only some of the areas are loaded from disk (e.g. where on sey «floppy there ‘fe some spare room on the system track, but not enough for ALL of 23), then initialisation of non-loaded 23 segment and Duffer areas must be selective, to avoid erasing data that have just arrived in RAH fro ‘ke. Te then deco! ‘idea to group the progran

‘above the BIOS wos sad to group buffers above

Whatever the system adopted, disk space for the aysten Ls not « proble amount of RAM allocated to the system is a problem however, sinc

Of the BIOS or 23 eat into the #PA. My extensively customized BIOS, toi yith workspaces, takes Up just under sk, and the 23 system uses 3k ceculting ina total system size of idk, including CoP, ‘and I am determined not to allow Ae to get any bigger. Since Iam aleo always trying to add features to the BIoS, Yan aleo looking for ways to economiee on space. One thing that T have recently done is to utilize some 80 spare bytes in the TCAP part of the ENV Seguent, to hold the system message and Clock string that are displayed on the (normaily locked) top Line of the screen. This has released 80 bytes in the BIOS ares for more code, but of course, means that that particular configuration of the BYOS will only work correctly 1a # 23 environment

‘The BIOS plus Workspace size 1c one of the important considerations, since this ie considerably Larger than BIOS plus Cold boot routines. T have no problea in expanding cold boot activities, and in providing extensive signon messages. The Maount of workepace aren needed 14 determined by the hardware used, and 20,

Felatively constant for a given system. This means that the BIOS peraanent cod is the part that needs to be kept in check. I have recently helped two friends Anetal £3 on systems based on Nascome, and the big problen was in the amount of space required by the BI0S code for the Keyboard routines. With a Winchester


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











Page 27 of 67