Chapter 4+5 CS008 UCR

Hardware

refers to the physical components of a computer

CPU

- Brain of the computer

- housed on the motherboard in the system unit

- processes commands (from software)

- controls functions performed by other components

Control Unit

executes instructions in CPU

Arithmetic Logic Unit (ALU)

- arithmetic calculations (addition, subtraction, etc.)

- logical calculations (comparisons)

Instruction Cycle

-sequence a CPU (control unit) goes through to execute a command

- fetch, decode, execute, store

Clock Speed

- The speed at which a processor executes the instruction cycle

gigahertz

- 1 billion cycles per second

Megahertx

- 1 million cycles per second

FLOPS (floating point operations per second)

- used to measure supercomputer performance

petaflop

- one thousand million million points per second

Multi-Core Processors

- two or more processors integrated on a single chip

- increases processing speed over a single-core processor

-reduce energy consumption over multiple separate processors

- dual core and quad core most common

GPU (Graphics Processing Unit)

- reduces processing required of the system CPU for graphics-intensive processes

-found on a video card

Parallel Processing

- distributes processing across multiple processors

- typically each process (program) is assigned to a processor by the Operating System

- can be simulated by hyper-threading

Pipelining

- used to improve performance of a single processor

- similar to an assembly line in a factory

- allows single processor to process up to 4 instructions at the same time

Cooling System

- keeps electronic components cool to prevent them from burning out

- heat sink (metal used to draw heat away from CPU), cooling fans, liquid cooling systems, usb powered fan for notebooks

System Unit

- case that encloses and protects a computer's internal components

Motherboard

- main circuit board of a computer, provides a way for devices to connect to a computer

Ports

- used to connect peripheral devices to the motherboard

USB

-most common type of port, can connect many types of devices (such as flash)

-Can connect up to 127 devices to a single port (USB hubs)

-Can provide power to devices

-Hot-swappable - devices can be plugged and unplugged without turning off computer

-Current version: USB 3.2 using USB-C connectors

Firewire

- legacy port (not found in newer computers)

- can connect up to 63 devices to a single port, hot-swappable

- mostly used for digital cameras

Thunderbolt

- can't connect many types of peripheral devices

- thunderbolt 2 is the standard on most apple computers

- about the same speed as USB 3.2

- can connect up to 6 devices using one port

Bluetooth

- short range wireless technology used to connect many types of peripheral devices

- devices need to be paired

BIOS (basic input/output system)

- used to boot the computer

- a program stored on a chip on the motherboard

- uses settings stored in a CMOS chip which uses battery to keep data from being erased when computer turned off

Random Access Memory (RAM)

- temporary storage used by a computer to hold instructions and data while they are in use

- also known as main memory

memory boards

- small circuit boards that contain memory chips

- easy to add memory to desktops

Cache Memory

- CPU fetches instructions and data from memory and stores results to RAM during the instruction cycle

Storage Devices

- store instructions and date when they are not being used

- contents not lost when power turned off

- larger capacity, cheaper, slower than RAM

Optical Disks

- a laser beam is used to read data

- can be read-only (ROM), recordable, or rewritable

-ex. CDs, DVDs, Blu-Ray

Flash Memory (storage)

- a non-volatile form of memory that can be electrically erased and programmed

- has no moving parts

- very reliable

Solid-State Drives (SDDs)

- can be used in desktop and notebook computers instead of regular hard drive

- much more expensive

- more reliable, faster to access

- usually smaller capacities

Flash Drives

- portable storage

- small portable solid-state drive

- can connect to a computer via a Usb port

Memory Cards

- portable storage used to expand the storage of smartphones, digital cameras, and other devices

Hard drives

- the primary mass-storage device in most computers

- holds the operating system

- most inexpensive type of storage device

- data stored magnetically on metal platters

- can be internal or external

input devices

- used to enter data into a computer system

Keyboard

- most commonly used input device

- QWERTY layout most common (designed to be slow)

-Dvorak layout more efficient but not widely used

pointing devices

- moves a cursor on the computer screen

- mouse, touchpad, touchscreen

optical scanners

- scans a page

- optical, barcode, or QR code

CRT (cathode ray tube) monitors

- big bulky heavy

- legact technology

LCD (liquid crystal display) monitors

- thinner, lighter

- originally developed for portable computers

Projectors

- produce larger output than a monitor

- used in presentations

Video Cards

- provides the data signal and connection for a monitor or projector

- can have own memory

ink jet printers

- most popular type of personal printer

- sprays droplets of liquid ink onto printer

Dye-Sublimation Printers

- high end printers mainly used for printing photographs

thermal printers

- applies heat to specially coated heat-sensitive paper to produce output

- mainly used to print receipts

- output can fade over time

three-dimensional printers

- can create objects such as prototypes and models

- used for dental and medical imaging

laser printers

- most common business printer

- uses powdered ink cartridge that lasts about twice as long as liquid ink cartridges

- faster than inkjet

Adaptive Technology

- used by individuals with disabilities to interact with technology

- spurred by the Americans With Disabilities Act (ada)

Communication Devices

- enables a device to connect to other devices on a network

Application software

"High level" software that performs a useful task for the user

Operating System

Low-level software that controls the computer hardware

-Manages Hardware

-Provides a user interface.

-Manages system resources, such as the CPU, memory, storage devices, etc.

-Communicates with peripheral devices through device drivers.

Manages Hardware

-Hides the complexity of the hardware from the user.

-Tasks that would be extremely difficult (such as saving a file) become simple (for the user).

User Interface (UI)

Determines how the user interacts with the computer.

Command-line user interface

-Older type of UI

-Instructions must be typed in

Graphical user interface (GUI)

-Newer type of UI

-Lets user point and click on graphic objects such as icons and buttons

-Easier to use than command-line UI

Managing the Processor

-Single-tasking versus multi-tasking

-In a single-tasking OS, only one program can be executed at a time.

-In a multi-tasking OS, multiple programs can be executed at the same time.

Managing Memory (RAM)

-The OS manages the memory for all programs and data files.

-All programs executed and data files opened are loaded into separate areas in memory.

-These memory areas should never overlap one another.

-If there is an error with memory management, computer usually crashes:

-Blue screen of death (Windows)

-Grey screen of death (MacOSX)

Virtual Memory

-Allows users to open up more applications and data files than can physically fit in the computer's memory (RAM).

-A special file on the main storage device, called a swap file, is created.

-When not enough room in memory, some content is copied to the swap file to free up space (a process known as paging).

-When content currently in swap file needs to be accessed, it is copied back to memory (likely causing other content in memory to be copied to swap file).

-Paging slows down the system... if it happens too frequently, computer can become totally unresponsive (thrashing).

Managing System Resources

-Ensures only one process at a time can access a hardware device.

-Access to other hardware (hard drives, etc.) work in a similar manner.

Multiple print jobs

A printer cannot print multiple docs at a time, so for each print request, the OS sees if the printer is in use. If it is not, the print request (job) is sent to the printer immediately, otherwise it is put in a queue. As each print job finishes, the OS checks the queue and sends the next job to the printer.

Peripheral Devices

-Operating system has to communicate with printers and other peripheral devices that may be plugged into the computer.

-Small programs known as device drivers are used for this.

-Device drivers written by company that creates the hardware.

-Acts as a translator... translates instructions from the OS to format the device understands.

PnP (Plug-and-Play)

Ability for the OS to recognize when a new device has been plugged in... it determines the device driver needed and automatically installs it if possible.

APIs

-Stands for Application Programming Interface

-Allows application programs to call API functions to have the operating system perform low-level tasks such as saving a file to a storage device.

-Makes writing software easier since programmers do not need to know hardware details.

Desktop Operating Systems

-MS-Windows

-Mac OSX

-Linux

MS-Windows

-First version was Windows 95 (1995).... Current is Windows 11

-Previous versions of Windows (i.e. Windows 3.1) were NOT operating systems, but application programs that ran on MS-DOS.

-Most popular OS (~75% of desktops/portable run some version of Windows).

-Considered to be less stable (i.e. crashes more often) and less secure (i.e. higher probability of being infected with a computer virus) than Mac OSX.

-Windows systems are much less expensive than Macs.

Mac OS

-Originally released in 1984.

-(Almost) first commercial computer to use a GUI.

-Much, much more expensive than MS-DOS/MS-Windows computers of the time.

-Replaced by Mac OSX in 2001.

Mac OSX

-First released in 2001.

-Completely new OS (based on UNIX and NeXTStep) and hardware.

-Considered more stable (less likely to crash) and more secure (less likely to be infected with a computer virus) than Windows.

-More expensive (often by 1.5-3 times) than Windows computers.

-~ 11% market share

Linux

-Open Source, so can download for free, including source code

-Multiple versions (Red Hat, Ubuntu, openSUSE, ChromeOS, etc.)

-Most commonly installed on IBM-PC computers (instead of MS-Windows)

-Less software available than for MS-Windows or MacOSX

-~ 2% market share

Configuring Desktop Operating Systems

-MS-Windows: Control Panel / Settings Window

-Mac OSX: System Preferences

-User Accounts

User Accounts

-Standard Standard Account

-Administrator Account

-Others (child, guest)

Embedded Operating Systems

-A specialized OS that runs in various electronic devices

-Very small, normally fits on a single chip

-Examples: GPS devices, ATMs, sensors, microwave ovens, thermostats, etc.

Mobile Operating Systems

-Operating systems that run on mobile devices such as smartphones and tablets

-More full-featured than embedded OS's but not as full-featured as desktop OS's

-Apple iOS

-Google Android

Apple iOS

-Scaled down version of Mac OSX used in iPhones and iPads

-Proprietary - found only on Apple devices

-More expensive (usually)

-"Ecosystem" tightly controlled, can only install apps from Apple App Store

-Personal data is kept more private than with competitors

-Leading mobile OS by company (but not overall)

Google Android

-Open source

-Based on Linux

-Found in devices from many companies (Samsung, Nokia, LG, etc.)

-Less restrictive; recommended apps be downloaded from Google Play Store, but can download from anywhere

-Less privacy for personal data

-Leading mobile OS overall

Network Operating Systems (NOS)

-Used in client-server networks

-A multi-user operating system that controls the software and hardware running on a network

-Allows multiple client computers to communicate with the network server to share resources, run applications, etc.

-Provides services such as user accounts, security, file and print services, Internet and email services, etc.

-Allows for centralized management

-Windows Server, Linux, Mac OSX, Unix

Unix

-The oldest and most powerful operating system (early 1970's)

-Versions run on multiple types of computers

-With over 200 commands, has reputation for being hard to learn

-Often used to manage networks (i.e. NOS)

-Most other operating systems based on UNIX

Peer-to-Peer Network

-Type of network normally used at home

-Each computer/device is considered equal

-No centralized authority (no common user accounts, for example)

-Each device can share its resources with other devices

Utility Software

-A type of system software used to perform computer maintenance

-Disk utilities

-Security utilities

Disk Formatting Utility

-Prepares a hard disk to store files by setting up the file system

-Only needs to be done once

-Creates File system

data is stored and retrieved

-MS-Windows: NTFS (latest) and FAT

-Mac OSX: APFS (latest) and HFS+

Firewall

a device or software that blocks unauthorized access to a network or an individual computer

Antivirus program

protects against computer viruses (and worms and Trojan horses)

Antispyware program

protects against spyware and adwareprotects against spyware and adware

Check Disk

checks for problems with the physical disk itself and for problems with the file system

Optimize Drive

defragments a hard drive to improve efficiency

Disk Cleanup

looks for files that can be safely deleted to free up disk space

Troubleshooting

-Reboot

-Task Manager (MS-Windows) / Activity Monitor (Mac OSX)

Reboot

most common "solution" when something goes wrong

Task Manager / Activity Monitor

-Used to view processes (programs) running on the computer

-Can force processes to quit

-Can also view how much memory each process is using and how much of the CPU it is using

System software

"Low level" software that makes the computer run