CompTIA A+ Test Prep – Operating Systems

Review hardware (hands on)
Motherboard
Exp cards
Hard drive

Chapter 1 – cont.

Multitasking –
Cooperative = task switching
Preemptive = true multitasking

Operating Systems – (P 34)

Win3x – cooperative; an environment, not an OS. 16 bit

Win9x – preemptive; uses virtual machines. 32 bit OS with 16 bit code included. ME is based on the 9x kernel. Has enough 16 bit code to run slower than NT on a true 32 bit CPU (Pentium MMX)

Unix – different distributions led to development of open source versions. Unix was open source, but not free

WinNT – preemptive, 32 bit. Supports multiprocessing, designed for client – server environment. Uses virtual DOS / DOS emulation to offer command line environment – no DOS in the code.

Win2K – suite of OS’. 1st MS OS that requires CPU greater than x86 and >16 Mb RAM. Introduced Active Directory.

MacOS – runs on MACs / MAC clones only

Operating System Modes:

Real Mode – 16 bit, program has direct access to RAM, single-tasking (NT / 2K uses virtual real mode)

Protected Mode – 32 bit, OS manages program interaction with RAM, access to extended memory

Virtual memory – swap file – used by protected mode

Filenames: 8.3, Long File Name

Directories:
Root
Subfolders / directories

Paths to files
.exe, .com, .bat

Launching an app: summarized on P. 44

Chapter 2:

System Bus
IRQ – hardware, software, cascading, polling
I/O
Memory addresses
DMA – DACK, DRQ, cascading
Data
Voltage
Control signals

Review Boot process

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Note: These are notes from my lectures as an IT instructor. Notes are from 1999-2001, so there may be little relevance to contemporary technologies. Still, it seemed like a shame to delete all of this work, so here they are. I hope someone finds them helpful.