hardware dan pengertian wi-fi

Motherboards (Chapter 1)

>The motherboard is the main printed circuit board
>Contains the buses, or electrical pathways found in a computer. Buses allow data to travel among the various components.
>Accommodates CPU, RAM, expansion slots, heat sink/fan assembly, BIOS chip, chip set, sockets, internal and external connectors, various ports, and the embedded wires that interconnect the motherboard components.




Cooling Systems

>Electronic components generate heat. Too much heat can damage components.
>A case fan makes the cooling process more efficient.
>A heat sink draws heat away from the core of the CPU. A fan on top of the heat sink moves the heat away from the CPU.
>Fans can be dedicated to cool the Graphics-processing unit (GPU).




ROM and RAM

>Read-only memory (ROM)
>ROM contains the basic instructions for booting the computer and loading the operating system are stored in ROM.
>Random-access memory (RAM)
>RAM is temporary storage for data and programs that are being accessed by the CPU
>RAM is volatile memory, which means that the contents are erased when the computer is powered off
More RAM means more capacity to hold and process large programs and files, as well as enhance system
performance.



Memory Modules

>Memory modules are memory chips that have been soldered on to a special circuit board for easy installation and removal.
>Dual Inline Package (DIP) is an individual memory chip.
>Single Inline Memory Module (SIMM) is a small circuit board that holds several memory chips.
>Dual Inline Memory Module (DIMM) is a circuit board that holds SDRAM, DDR SDRAM, and DDR2 SDRAM chips.
>RAM Bus Inline Memory Module (RIMM) is a circuit board that holds RDRAM chips.
>Small Outline DIMM (SODIMM) is a smaller, more condensed version of DIMM which provides random access
data storage that is ideal for use in laptops, printers, and other devices where conserving space is desirable.
>The speed of memory has a direct impact on how much data a processor can process because faster memory
improves the performance of the processor. As processor speed increases, memory speed must also increase.



Adapter Cards

>Adapter cards increase the functionality of a computer by adding controllers for specific devices or by replacing
malfunctioning ports.
>Examples of adapter cards:
>Sound adapter and video adapter
>USB, parallel, and serial ports
>Network Interface Card (NIC), wireless NIC, and modem adapter
>Types of expansion slots:
>Peripheral Component Interconnect (PCI)
>Advanced Graphics Port (AGP)
>PCI-Express 



Hard Drives and Floppy Drives

>Hard drives and floppy drives read or write information to magnetic storage media.
>They may be fixed or removable.
>The hard disk drive (HDD) is a magnetic storage device. The storage capacity is measured in gigabytes (GB).
>Magnetic hard drives have drive motors designed to spin magnetic platters and move the drive heads.
>Solid state drives (SSDs) do not have moving parts, which results in faster access to data, higher reliability,
reduced power usage.
>A floppy disk drive (FDD) is storage device that uses removable 3.5 inch floppy disks that can store up to 1.44
MB of data.

Optical Drives, Flash Drives and Drive Interfaces

>An optical drive is a storage device that uses lasers to read data on the optical media. The three types are CD,
DVD and BD.
>A flash drive is a removable storage device that connects to a USB port. A flash drive uses a type of memory
that requires no power to maintain the data.
>Some common drive interfaces are:
>Integrated Drive Electronics (IDE)
>Enhanced Integrated Drive Electronics (EIDE)
>Parallel ATA (PATA)
>Serial ATA (SATA) and External SATA (eSATA)
>Small Computer System Interface (SCSI)


Internal Cables

>Internal power cables (Molex and Berg) connect drives and fans to the motherboard.
>Front panel cables connect the case buttons and lights to the motherboard.
>Data cables connect drives to the drive controller.
>Floppy disk drive (FDD) data cable
>PATA (IDE) data cable
>PATA (EIDE) data cable
>SATA data cable
>eSATA data cable
>SCSI data cable


Input Devices

>Input devices are used to enter data or instructions into a computer:
>Mouse and Keyboard
>KVM switch
>Digital camera and digital video camera
>Biometric authentication device
>Touch screen
>Scanner



Output Devices

>Monitors and Projectors:
>Cathode-ray tube (CRT) monitor is the most common monitor type. Most televisions also use this technology.
>Liquid crystal display (LCD) is commonly used in laptops and some projectors. LCD comes in two forms,
active matrix and passive matrix.
>Digital light processing (DLP) is another technology used in projectors.
>Monitor resolution refers to the level of image detail that can be reproduced. Higher resolution settings produce
better image quality.
>Printers and Fax Machines are output devices that create hard copies of computer files.
>Scanners create electronic file version of paper documents.
>Speakers and headphones are output devices for reproducing audio signals.


System Resources

>System resources are used for communication purposes between the CPU and other components in a computer.
>There are three common system resources:
>Interrupt Requests (IRQs)
>Input/Output (I/O) Port Addresses
>Direct Memory Access (DMA) 




sumber : http://idasetia.blogspot.com/2012/03/modul-cisco-academy-chapter-1-version.html#more




Pengertian "WI-FI" (Chapter 13)



Wi-Fi (atau Wi-fi, WiFi, Wifi, wifi) merupakan kependekan dari Wireless Fidelity, memiliki pengertian yaitu sekumpulan standar yang digunakan untuk Jaringan Lokal Nirkabel (Wireless Local Area Networks - WLAN) yang didasari pada spesifikasi IEEE 802.11. Standar terbaru dari spesifikasi 802.11a atau b, seperti 802.16 g, saat ini sedang dalam penyusunan, spesifikasi terbaru tersebut menawarkan banyak peningkatan mulai dari luas cakupan yang lebih jauh hingga kecepatan transfernya.

Awalnya Wi-Fi ditujukan untuk pengunaan perangkat nirkabel dan Jaringan Area Lokal (LAN), namun saat ini lebih banyak digunakan untuk mengakses internet. Hal ini memungkinan seseorang dengan komputer dengan kartu nirkabel (wireless card) atau personal digital assistant (PDA) untuk terhubung dengan internet dengan menggunakan titik akses (atau dikenal dengan hotspot) terdekat.

Wi-Fi dirancang berdasarkan spesifikasi IEEE 802.11. Sekarang ini ada empat variasi dari 802.11, yaitu: 802.11a, 802.11b, 802.11g, and 802.11n. Spesifikasi b merupakan produk pertama Wi-Fi. Variasi g dan n merupakan salah satu produk yang memiliki penjualan terbanyak pada 2005.

Spesifikasi.

802.11b 11 Mb/s 2.4 GHz b
802.11a 54 Mb/s 5 GHz a
802.11g 54 Mb/s 2.4 GHz b, g
802.11n 100 Mb/s 2.4 GHz b, g, n

Di banyak bagian dunia, frekuensi yang digunakan oleh Wi-Fi, pengguna tidak diperlukan untuk mendapatkan ijin dari pengatur lokal (misal, Komisi Komunikasi Federal di A.S.). 802.11a menggunakan frekuensi yang lebih tinggi dan oleh sebab itu daya jangkaunya lebih sempit, lainnya sama.

Versi Wi-Fi yang paling luas dalam pasaran AS sekarang ini (berdasarkan dalam IEEE 802.11b/g) beroperasi pada 2.400 MHz sampai 2.483,50 MHz. Dengan begitu mengijinkan operasi dalam 11 channel (masing-masing 5 MHz), berpusat di frekuensi berikut:

* Channel 1 - 2,412 MHz;
* Channel 2 - 2,417 MHz;
* Channel 3 - 2,422 MHz;
* Channel 4 - 2,427 MHz;
* Channel 5 - 2,432 MHz;
* Channel 6 - 2,437 MHz;
* Channel 7 - 2,442 MHz;
* Channel 8 - 2,447 MHz;
* Channel 9 - 2,452 MHz;
* Channel 10 - 2,457 MHz;
* Channel 11 - 2,462 MHz






sumber : http://om-anca.blogspot.com/2008/10/pengertian-wi-fi.html