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Operating system
In computing, an operating system (OS) is the system software responsible
for the direct control and management of hardware and basic system
operations.
Colloquially, the term is most often used to mean all the software which
"comes with" a computer system before any applications are installed.
The operating system ensures that other applications are able to use memory,
input and output devices and have access to the file system. If multiple
applications are running, the operating system schedules these such that all
processes have sufficient processor time where possible and do not interfere
with each other.
Examples of operating systems
* UNIX
* GNU/Linux
* Microsoft Windows
* Mac OS
* MVS
* OpenVMS
Classifications and Terminology
An operating system is conceptually broken into three sets of components: a
shell, a kernel and low-level system utilities. As the name implies the
shell is an outer wrapper to the kernel which in turn talks directly to the hardware.
Hardware Kernel Shell Applications
In some operating systems the shell and the kernel are completely separate
entities, allowing you to run varying combinations of shell and kernel (eg
UNIX), in others their separation is only conceptual (eg Windows).
Kernel design ideologies include those of the monolithic kernel, the
microkernel and the exokernel. Traditional commercial systems such as UNIX
and Windows use a monolithic approach, the trend in more modern systems is
to use a microkernel (such as in QNX, BeOS, Windows NT etc) there are a few
exceptions such as Linux which still use a monolithic kernel . The
microkernel approach is also very popular among research OSes. Many embedded
systems use ad-hoc exokernels.
This content from Wikipedia is licensed under the GNU Free Documentation License.
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A-Power 480W ATX Power Supply with 4-In Fan &SATAA-Power 480W ATX Power Supply with 4-In Fan &SATA ** A-Power 480W ATX Power Supply **This 480-watt ATX power supply from A-Power is ready to power your system! Featuring six Molex connectors and a Serial ATA power connector, you can run all your devices and then some! A large 4.5-inch fan helps keep things running cool!General Features:- 480-watt power supply- 4.5-inch fan- One (1) 14-inch ATX power connector- One (1) 14-inch Auxiliary ATX power connector- One (1) 14-inch 12V ATX power connector- One (1) 14-inch SATA power connector- Six (6) 14-inch 4-pin large Molex power connectors- One (1) 14-inch 4-pin small floppy power connector- Supports Intel Pentium 4 and AMD motherboards- Low noise and ripple- Short circuit and over-voltage protection- Thermal overload cut-off protectionPower Specifications:- 115V, 230V switchable power supply- +3.3V @ 28A- +5V @ 38A- +12V @ 17A- -12V @ 0.8A- -5V @ 0.5A- +5 Vsb @ 2AUnit Dimensions:- 3.25 x 6 x 5.5-inches (H x W x D, approximate)Retail Package Includes:- A-Power 550-watt ATX power connector- Power cordNotes:- Thispower supply has no regulatory approvals Compatibility/Requirements/Disclosures: ** Requirements *** ATX case* ATX motherboard* Available power outlet More ...
Pocket Printer A6 for PDAsPocket Printer A6 for PDAs ** De-Branded Pocket Printer A6 Portable Printer **This pocket printer A6 is a compact and lightweight mobile printer perfect for the on-the-go business professional. This pocket printer A6 uses advanced thermal technology, meaning you never have to replace messy ribbons or ink tanks. Print from your Palm, Pocket PC, laptop or desktop computers with ease. Featuring wireless infrared connectivity for use with infrared enabled devices, the Pocket Printer A6 is ideal for mobile computing. For non-infrared enabled computers, you can use the included serial cable.General Features:- Infrared wireless and serial port connectivity- Ultra-slim, compact and battery powered- Thermal technology for reliable silent operation- Black and white output- Works with Palm OS and Pocket PC PDAs- Works with Windows PCsTechnical Specifications:- Printing Method: Direct thermal- Print color: Monochrome- Print Resolution: 400 dpi- Active Image Width: 3 3/4 (95mm)- Media Width: 4 1/8 (105mm)- Media Length: Sheet - 5 3/4 (148mm), Roll - 8'2 (2.5m)- Media Thickness: 60-90um- Interface: IrDA 1.0, Serial RS-232- Print Speed: 2ppm (approximately)- Auto shut-off: 3 minutes with batteries or 1 hour using AC power adapter- Power Consumption: 15W- Power Source: 4 AA alkaline (included) AC Adapter 9V, 1.5A (included)- Printer Weight: 8.75 ounces (250g) without batteries or paper ounces (400g) with batteries and roll paper- Printer Dimensions: 5.85 x 4.25 x .992 (150mm x 109mm x 25.4mm)Retail Package Includes:- Pocket Printer A6 with built-in infrared- Serial Printer Cable- Owner's Manual- AC Power Adapter- One (1) Roll A6 Printer Paper- Printer Travel Bag- 4 AA Batteries- Driver CD containing:- Windows 98, 98SE, 2000, ME printer drivers- Pocket Printer application softwareNotes:- This is a De-branded SiPix PPA6 - Color may vary from black or blue Compatibility/Requirements/Disclosures:** Requirements *** PC Requirements:* Pentium processor or higher* Microsoft Windows 98/98SE/ME/2000/XP* IrDA capable or Serial Port* CD-ROM Drive* VGA Color Monitor* At least 4 MB available hard disk space* Pocket PC Requirements:* Pocket PC devices running Windows CE 2.0-3.1 (devices using StrongARM Hitachi SH3 or MIPS processors)* IrDA capable* ActiveSync to PC* Palm Requirements:* Palm powered devices using Palm OS 3.1-4.0* Infrared capable* Hot-sync to PC** Disclosures *** This is a De-branded SiPix PPA6 * Color may vary from black or blue More ...
Mini Wireless Color Camera with MicrophoneMini Wireless Color Camera with Microphone ** Miniature Wireless Camera with Microphone **Keep an eye on valuables and loved ones with this tiny wireless camera! With up to 150-foot range, it's easy tokeep track of anything!General Features:- 380-lines resolution- 150-foot range (no obstacles)- 60 Hz scan frequency- 3 LUX illumination- 900 - 1200 MHz output frequency- Built-in microphone- NTSC- Full motion real time color video with no delay - Camera runs on 9-volt battery or AC adapter (battery notincluded)- Composite video connections on receiverRetail Package Includes:- Miniature camera with built-in microphone- Receiver- RCA video cable- 9-volt battery adapter for camera- Camera AC adapter (120V, 60 Hz; 7.5 V, 200 mA)- Receiver AC adapter (120V, 50 Hz; 12V 500 mA)- Antenna- ManualNotes:- Regulatory approvals are on box, but not on unit Compatibility/Requirements/Disclosures:** Requirements *** Available power outlet(s)* 9-Volt battery for camera if not using power adapter* Standard TV or VCR with RCA (composite) video input** Disclosures *** Regulatory approvals are on box, but not on unit* This product is not intended for use in unauthorizedsurveillance, wiretapping, eavesdropping or other uses which violate state or federal laws. More ...
Intel Pentium 90MHz Socket 7 CPUIntel Pentium 90MHz Socket 7 CPU ** Intel Pentium 90MHz Socket 7 CPU **General Features:- Original Intel Pentium Classic- 90MHz- Socket 7- Ceramic PGA packaging- CPU OnlyCompatibility/Requirements/Disclosures:** Requirements *** Socket 7 Heatsink & Fan* Motherboard that supports 90MHz Pentium CPU's More ...
Treasures of the Bible Express EditionTreasures of the Bible Express Edition Whether you're a serious student of the Bible, or just a person who wants a better understanding of the Christian faith, the content contained in Treasures of the Bible will be an invaluable source of information and understanding. 4 software programs packed into 3 CD-ROMs! Windows 95/98/2000/ME/XP. More ...
IBM Cel 550MHz 64MB 5GB CD No FDD 13.3'' TFT - BIBM Cel 550MHz 64MB 5GB CD No FDD 13.3'' TFT - B ** IBM ThinkPad iSeries Celeron 550 MHz Notebook **The IBM ThinkPad i Series notebook computer delivers fantastic performance at an attractive price. It features an Intel Celeron 550 MHz processor, 64 MB RAM, and a 5 GB hard disk drive. The 13.3-inch TFT screen provides clear, crisp viewing at 1024 x 768 resolutions. Audio, video, modem and Ethernet are all integrated as well. Get this IBM ThinkPad i Series notebook today and join the notebook revolution!General Features:- Grade B- Intel Celeron 550 MHz processor- 64 MB RAM (192 MB maximum)- 5 GB hard drive- CD-ROM drive (speeds may vary)- No Floppy disk drive- Silicon Motion LynxEM4+ integrated video w/ 4 MB VRAM- Integrated audio with built-in speakers- Integrated modem- Integrated Ethernet controller- 85-key keyboard w/ trackpoint mouse- 13.3-inch TFT display with 1024 x 768 maximum resolution- Ni-MH rechargeable battery (9.6V, 4.5AH)Expansion Slots:- Two (2) PCMCIA Type I/II slots or one Type IIII/O Ports:- One (1) PS/2 port- One (1) 15-pin standard VGA connector- One (1) 25-pin standard parallel port- Two (2) USB ports- One (1) RJ-11 standard phone jack- One (1) RJ-45 standard Ethernet jack- Microphone and headphone jacksRegulatory Approvals:- UL- FCC- CEPackage Includes:- IBM ThinkPad i Series refurbished notebook- AC adapter (100-240V, 50/60Hz)- Power cordNotes:- IBM Type: 1171-71U- No Floppy drive- Battery is not covered under the warranty- The battery is not guaranteed to hold a charge- Does not include OS, drivers, documentation, etc. Compatibility/Requirements/Disclosures:** Requirements *** Operating System (OS)* Drivers for installed devices* Available power outlet** Refurbished Notebook Grades *** Grade B * Notebook is in very good condition * Has Cosmetic Blemishes, examples of which are (but not limited to): * Scratches in case * Scratches in the screen * Hairline crack in case * Dead pixels (5 or less) * Missing doors * May be missing manual, drivers, operating system, carrying cases * Battery is not guaranteed to hold a full charge * Battery is not covered under warranty * All specific issues will be noted in the ad * Etc. More ...
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