scooper@brl-tgr.ARPA (Stephan Cooper ) (08/13/85)
What does the scroll lock key on the IBM PC do? Is it like a Cntrl-S? The Tandy 1000 doesn't have this key, so what sequence can I use to simulate it? -Steve
APratt.osbunorth@XEROX.ARPA (08/14/85)
ScrollLock is a very special key on the PC keyboard. It's so special, MS-DOS doesn't know it exists. The result is that striking the key normally DOES NOTHING. Some programs, like SideKick, pay attention to it, though. At a more technical (BIOS) level, Scroll Lock acts like Num Lock and Caps Lock: striking it once sets a bit in the BIOS data area (beginning at 00400 absolute), and striking it again clears the bit. You can get these "shift state" bits from the BIOS with a call to the keyboard interrupt (check the Technical Reference manual). Since it's not a "key" the way the spacebar and the letter "A" are keys, it would be hard to simulate it on a Tandy keyboard, unless Tandy had that in mind when they designed their keyboard software. The intended use of Scroll Lock, of course, is to let you read text before it scrolls away. It's a toggle, so you hit it once to "lock" scrolling and read the text, then hit it again to "unlock" scrolling and proceed. There are some public-domain utilities, probably available from Simtel-20, which make the Scroll Lock key do its thing in normal MS-DOS operation. I couldn't name one, but maybe someone else can. It's important to know that the ScrollLock key is also the Break key: Ctrl- ScrollLock causes "break" processing in a more catastrophic way than Ctrl-C. I expect the Tandy keyboard has something similar to this, but I don't know. -- Allan Pratt
slerner@sesame.UUCP (Simcha-Yitzchak Lerner) (08/20/85)
> > ScrollLock is a very special key on the PC keyboard. It's so special, MS-DOS > doesn't know it exists. The result is that striking the key normally DOES > NOTHING. Some programs, like SideKick, pay attention to it, though. > > At a more technical (BIOS) level, Scroll Lock acts like Num Lock and Caps Lock: The above is quite correct, that the scroll lock is esentialy a shift state key. (Unlike another posting that was getting break and ctrl-num/hold mixed in) I do not have my manuals handy, but the tandy-1000 does have some strange key-combo that will emulate the scroll lock key, setting the proper bit at 40:17hex. If you can't find it in you manual, mail me a note and i'll look it up. -- Opinions expressed are public domain, and do not belong to Lotus Development Corp. ---------------------------------------------------------------- Simcha-Yitzchak Lerner {genrad|ihnp4|ima}!wjh12!talcott!sesame!slerner {cbosgd|harvard}!talcott!sesame!slerner slerner%sesame@harvard.ARPA