Doug.Geoffray@f8.n369.z1.fidonet.org (Doug Geoffray) (09/17/90)
Index Number: 10403
[This is from the Blink Talk Conference]
WW> That brings up my question...I noticed that most speech
WW> programs seem to use hardware cursor as the default, and yet I
WW> am not clear on what the difference is between hardware cursor
WW> tracking and whatever they call the other one. Could somebody
WW> explain this to me in very simple terms?
Willie,
Well, I will give it a shot.
There are two ways to get the current cursor position.
The hardware approach means you ask the video card directly for the current
cursor position. Since the video card is the guy responsible for displaying
the cursor on the screen he always knows where the cursor is. This method
will always give you the correct cursor address.
The other method is BIOS. Most programs would rather let BIOS (Basic
Input Output System) handle the dirty work of telling the video card
where to place the cursor. This way the applications program does not
have to care if you are using a monochrome or color system. Simply
call a BIOS routine and give it the column and line and the cursor
will be moved. When BIOS does this it keeps track internally the position
of the cursor. Through another call to BIOS, an applications program
or screen reader can get the current cursor position. But BIOS does not
ask the hardware directly, it simply reads its internal variable of the
last cursor position it moved it to.
The problem with BIOS is if an applications program is moving the cursor
by directly talking to the video card, BIOS still thinks the cursor
is where it last placed it. Therefore calling BIOS for the cursor position
may not always give you the actual cursor position.
I hope you can see the difference. If you do, you may be asking why not
simply use hardware all the time since it will always give you the correct
cursor position. Good question Willie.
There are times when you don't really want the actual video cursor. One
good example is LP-DOS. LP-DOS is a large print program. It simulates a
large cursor on the screen and placed the real cursor off the screen. If
you asked the hardware where the cursor is, it would report it being off
of the screen everytime. Not very usefull. However, LP-DOS is intercepting
the BIOS routines and faking it out as to where the cursor is. This means
If the screen reader or what ever calls BIOS for the cursor position,
LP-DOS intercepts and returns with its fake cursor position.
Isn't life great!
Well Willie, I hope all this garbage makes some sence to you. It really
is not as difficult as I might have led to believe. The key is a good
screen reader really needs the capability of using both methods. Depending
on the applications program, you may have to use BIOS or hardware.
Regards,
Doug
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Uucp: ..!{decvax,oliveb}!bunker!hcap!hnews!369!8!Doug.Geoffray
Internet: Doug.Geoffray@f8.n369.z1.fidonet.orgTandy.Way@f6.n377.z1.fidonet.org (Tandy Way) (09/20/90)
Index Number: 10461
[This is from the Blink Talk Conference]
may I complicate things more her doug rather than quoting yours and
willies responses. in flipper there are actually three types of
tracking as they describe it. 1. hardware curser. 2. "forced
inversed curser". 3. normal curser. and then they have two types of
bar tracking "automatic spreadsheet and lightbar tracking" and
"manual lightbar tracking". how does those terms relate to the way
that vocal eyes does things?
tandy
... (A)bort, (R)etry, (F)ail, (G)o fix the coffee
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