A+ Guide to Managing and Maintaining Your PC Fifth Edition Chapter 2 How Hardware and Software Work Together
You Will Learn About operating systems, what they are, and what they do How an OS interfaces with users, applications, and hardware How system resources help hardware and software communicate 2
Introducing Operating Systems Software that controls a computer Acts as a middleman between applications and hardware Two main internal components Shell Kernel 3
OS as a Middleman 4
The Shell and the Kernel 5
Common Operating Systems DOS Windows 9x Windows NT, Windows 2000, and Windows XP Unix Linux OS/2 Mac OS 6
What an Operating System Does Provides user interface Stores, retrieves, and manipulates files and folders Manages applications Manages hardware 7
How an OS Provides a User Interface Command-driven interfaces Menu-driven interfaces Icon-driven interfaces 8
A Menu-Driven Interface 9
How an OS Manages Files and Folders Uses file system (FAT or NTFS) to track how clusters are used for each stored file Uses directories, subdirectories, and files Uses partitions and logical drives on hard drive 10
Tracks, Sectors, and Clusters 11
Files and Directories 12
Partitions and Logical Drives 13
How an OS Manages Applications Provides access to hardware resources Manages data in memory and in secondary storage Performs other background tasks 14
Loading Application Software Using the Windows Desktop Shortcut icon Start menu Run command Windows Explorer or My Computer 15
Using a Shortcut Icon to Load Software 16
Real and Protected Operating Modes Real (16-bit) operating mode CPU processes 16 bits of data at one time Software has real access to hardware Protected (32-bit) operating mode CPU processes 32 bits of data at one time More than one program can be running, each one protected from others Uses preemptive multitasking 17
16-Bit and 32-Bit Software 16-bit software Written for Windows 3.x Accesses data 16 bits at a time Programs should not infringe on resources of other programs that are running 32-bit software Written for Windows 95 and later Windows OSs 18
How an OS Manages Hardware Uses device drivers or the BIOS (system BIOS, startup BIOS, or CMOS setup) to interface with hardware Trend is to manage devices with device drivers rather than BIOS 19
How an OS Manages Hardware (continued) 20
How an OS Uses Device Drivers to Manage Hardware Device drivers provide OS with software necessary to control devices 16-bit read-mode drivers Supported by Windows 95/98 32-bit protected-mode drivers Supported by Windows 95/98, Windows Me, and Windows NT/2000/XP 21
How an OS Uses System BIOS to Manage Devices To communicate with simple devices (eg, floppy drives or keyboards) To access the hard drive 22
Using System BIOS 23
Using System BIOS (continued) 24
System Resources 25
System Resources (continued) Depend on certain lines on a bus on motherboard System bus components Data bus carries data Address bus communicates addresses (memory addresses and I/O addresses) Control bus controls communication (IRQs and DMA channels) 26
System Bus Components 27
Interrupt Request Number (IRQ) Line on a bus that device needing service uses to alert the CPU Managed by interrupt controller on motherboard Early motherboards: eight IRQs Second group of IRQs and second interrupt controller have been added to accommodate need for more devices 28
Common Assignments for First Eight IRQs 29
Second IRQ Controller 30
Viewing IRQ Assignments Microsoft Diagnostic Utility (MSD) for DOS Device Manager for Windows 2000/XP and Windows 9x 31
Viewing IRQ Assignments (continued) 32
Viewing IRQ Assignments (continued) 33
Memory Addresses Hexadecimal numbers assigned to RAM and ROM so the CPU can access both Used to access physical memory Often written in segment:offset form (eg, C800:5) 34
Memory Addresses (continued) 35
I/O Addresses Numbers CPU can use to access hardware devices 36
I/O Addresses (continued) 37
Common Assignments for I/O Addresses 38
Direct Memory Access (DMA) Channels Shortcut method that lets an I/O device send data directly to memory, bypassing the CPU 39
DMA Channels 40
OS Tools to Examine a System Device Manager System Information utility Microsoft Diagnostic Utility (MSD) 41
Device Manager Primary tool used to manage hardware devices under Windows 2000/XP and Windows 9x 42
Device Manager ( continued) 43
System Information Utility Gives similar, but more, information than Device Manager BIOS version in use Directory where OS is installed How system resources are used Information about drivers and their status Additional information about software 44
Using Windows System Information 45
Microsoft Diagnostic Utility (MSD) Useful for viewing information about the system, including: Memory Video Ports Device drivers System resources 46
Using MSD 47
Summary How hardware and software work together Different operating systems What they do How they work to control hardware devices How an OS provides the interface that users and applications need to command and use hardware devices 48