ALCATRAZ EMULATOR

by Kevin Gale



The Alcatraz loading system, apart from being fairly notorious in

Spectrum circles, is also the bane of all hackers. But more

importantly it uses an original screen build up routine while it

loads. And this is the part Kevin Gale has emulated in this, his

sensational program.



Method

I'm not even going to make a comment on how easy this program is to

use. [Sigh. Well, don't, then. JimG] Simply type in the listing, SAVE

it, and then RUN it. Now what's difficult about that? [There are

actually two listings, and the second one has to be entered first, as

it sets up the machine code and loads the main program. JimG]



The Features

(i)	LOAD SCREEN

	Select this option to load a normal screen picture from

	tape or Opus disk.

(ii)	EDIT SCREEN

	Select this option to design the way the screen loads.

	Your cursor is shown as a flashing square which can

	be moved around with the cursor keys. To select a

	square use 0: to unselect a square use 9. [The "unselect"

	option doesn't work. Compare lines 27/28. JimG] When your

	creativity is exhausted use Symbol Shift and M. Clear

	the screen with Symbol Shift and 1.

(iii)	SAVE DATA

	Select this option to save the screen data to tape or

	Opus disk; this is useful if you have not finished your

	loader design. Three pieces of data are saved, totalling

	23810 bytes.

(iv)	SAVE SCREEN

	When you've completed your design you can save it

	to tape for use in your own programs. This option can

	only be selected when the picture is complete. The

	picture is saved as a headerless file, 9984 bytes long.

	[I couldn't get this option to work either. It's not clear

	how the program decides that the picture is "complete". JimG]

(v)	SAVE LOADER

	Use this option to save  copy of the loader. It can be

	saved to any memory address from 23296-65441.

	The loader is 95 bytes long.

(vi)	WATCH SCREEN

	An option for all the voyeurs. You can view your toil as the

	program pretends the screen is loading.

(vii)	DEMO DATA

	This creates a demonstration loading pattern to impress you.

[There's an 8th option "LOAD DATA" which McCandless didn't bother to

explain. JimG]