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Unformatted text preview: of device was installed, and you would For More BS-IT Books, Notes & Assignments visit: www.bsit.zxq.net 2.6 Chapter Summary
Downloaded From: www.bsit.zxq.net 55 not be concerned with nonstandard features the card might have. At the BIOS level, you
would query the sound card (using its installed device driver software) and ﬁnd out whether it
belonged to a certain class of sound cards having known features. At the hardware level, you
would ﬁne tune the program for certain models of audio cards, taking advantage of each card’s
Finally, not all operating systems permit user programs to directly access system hardware.
Such access is reserved for the operating system itself and specialized device driver programs.
This is the case with all versions of Microsoft Windows beyond Windows 95, in which vital
system resources are shielded from application programs. MS-DOS, on the other hand, has no
2.5.2 Section Review
1. Of the four levels of input/output in a computer system, which is the most universal and
2. What characteristics distinguish BIOS-level input/output?
3. Why are device drivers necessary, given that the BIOS already has code that communicates
with the computer’s hardware?
4. In the example regarding displaying a string of characters, which level exists between the
operating system and the video controller card?
5. At which level(s) can an assembly language program manipulate input/output?
6. Why do game programs often send their sound output directly to the sound card’s hardware
7. Challenge: Is it likely that the BIOS for a computer running MS-Windows would be different from that used by a computer running Linux? 2.6 Chapter Summary The central processor unit (CPU) is where calculations and logic processing occur. It contains a
limited number of storage locations called registers, a high-frequency clock to synchronize its
operations, a control unit, and the arithmetic logic unit. The memory storage unit is where
instructions and data are held w...
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- Winter '13