Conditions of Use

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Basic knowledge about battery

Battery usage tips

• A new battery usually comes in a discharged condition and with a very low capacity. It is generally recommended to fully charge new battery packs before use. Refer to the user's guide of your electronic device for charging instructions.
• A new battery pack needs to be circled (fully discharged and recharged) three to five times to reach its optimum performance.
• Rechargeable battery will undergo self-discharging when left unused for a long period of time. Thus, it should always be stored in a fully charged state and kept in a cool, dry and clean place.
• To maintain the optimum performance of a battery pack, it is highly recommended to circle (fully discharging and recharging) it at least once a month.
• It is normal if a new battery gets warm when being charged or used. However, close attention should be paid if the battery pack becomes excessively hot. This may indicate there is a problem with the charging circuit of the electronic device. So, it is necessary to have it checked by a qualified technician.
• New batteries are hard to be charged. Sometimes, your electronic device may indicate a fully charged condition about 10 to 15 minutes when the new battery pack is being charged for the first time. When this happens, remove the battery pack and let it cool down for about 10 to 15 minutes then repeat the charging procedure. Sometimes, a new battery will suddenly refuse to be charged. If this happens, it is then suggested to remove the battery from the device and reinsert it.

Better use of battery

• Do not modify or disassemble.
• Do not incinerate or expose battery to excessive heat, which may result in an exposure.
• Do not expose battery to water or other moist matters.
• Do not pierce, hit, step on, crush or abuse the battery.
• Do not place battery in device for a long period of time if device is not being used.
• Do not short circuit the terminals or store your battery pack with metal objects such as necklaces or hairpins.

Frequently Asked Questions:

• 1.2 volts per cell for Ni-Cd and NiMH
• 3.6 or 3.7 volts per cell for Lithium Ion or Lithium Polymer
• 3 volts per cell for lithium primary
• 2 volts per cell for sealed lead acid
• 1.5 volts per cell for alkaline and carbon zinc

• 1.0 volt per cell for Ni-Cd and NiMH
• 1.75 volts per cell for sealed lead acid
• 2.75 volts per cell for lithium ion and lithium polymer
• 2.0 volts per cell for primary lithium
• 0.9 volts per cell for alkaline and carbon zinc

• 0 ~ 1% per day for Ni-Cd
• 0 ~ 2% per day for NiMH
• 0 ~ 0% per day for Lithium Ion and Lithium Polymer .

Learn more about screen

Measuring size of the laptop screen

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The most popular laptop screen size

The resolution of laptop screen

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Ways to find your screen resolution

• First , to find the best resolution by Google and anther search engine ;
• Second , to find the best resolution by checking packaging of laptop ;
• Third , to find the best resolution by official website .

• If your system is Windows 98 , Windows 2000 , Windows 2003 , Windows ME , Windows NT or Windows XP : Right-Click on Desktop => Properties => Setting => Resolution ;
• If your system is Windows Vista or Windows 7 : Right-Click on Desktop => Personalize => Graphics Options ;
• If your system is Linux , finding code of screen section in xorg.conf , as follow :
  Section "Screen"
  Identifier "Screen0"
  Device "Card0"
  Monitor "Monitor0"
  DefaultColorDepth 24
  SubSection "Display"
  Depth 24
  Modes "1024×768" "800×600" "640×480"
  EndSubSection
  EndSection
  The red part is resolution , first one after Modes is default .
• If your system is Mac OS : Click the Apple icon on upper left corner => Setting => Display .

Common screen resolution

The backlight type of laptop screen

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Choose backlight type of screen

The backlight type of screen

1. CCFL (Cold cathode fluorescent lamp) ;
1. 1-CCFL - contains 1 bulb (sometimes may call CCFL 1-Bulb);
2. 2-CCFL - contains 2 bulb (sometimes may call CCFL 2-Bulb);
2. LED (Light emitting diode) ;

The image of screen backlight type

1-CCFL

2-CCFL

LED

LED screen can never be used to replace a CCFL screen.

Learn more about Hard Driver ( Hard Disk Drive , call HDD follow)

A hard disk drive ( HDD , also hard drive or hard disk ) is a non-volatile, random access digital data storage device. It features rotating rigid platters on a motor-driven spindle within a protective enclosure. Data is magnetically read from and written to the platter by read/write heads that float on a film of air above the platters.

Introduced by IBM in 1956, hard disk drives have decreased in cost and physical size over the years while dramatically increasing in capacity. Hard disk drives have been the dominant device for secondary storage of data in general purpose computers since the early 1960s. They have maintained this position because advances in their recording density have kept pace with the requirements for secondary storage. Today's HDDs operate on high-speed serial interfaces: i.e., serial ATA (SATA) or serial attached SCSI (SAS).

Capacity of the Hard Drive

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The capacity of an HDD may appear to the end user to be a different amount than the amount stated by a drive or system manufacturer due to amongst other things, different units of measuring capacity, capacity consumed in formatting the drive for use by an operating system and/or redundancy.

Units of measuring capacity

The capacity of hard disk drives is given by manufacturers in megabytes (1 MB = 1,000,000 bytes), gigabytes (1 GB = 1,000,000,000 bytes) or terabytes (1 TB = 1,000,000,000,000 bytes). This numbering convention, where prefixes like mega- and giga- denote powers of 1000, is also used for data transmission rates and DVD capacities. However, the convention is different from that used by manufacturers of memory (RAM, ROM) and CDs, where prefixes like kilo- and mega- mean powers of 1024.

When the unit prefixes like kilo- denote powers of 1024 in the measure of memory capacities, the 1024n progression (for n = 1, 2, …) is as follows:

kilo = 210 = 10241 = 1024
mega = 220 = 10242 = 1,048,576
giga = 230 = 10243 = 1,073,741,824
tera = 240 = 10244 = 1,099,511,627,776
and so forth.

show as the table :

The practice of using prefixes assigned to powers of 1000 within the hard drive and computer industries dates back to the early days of computing. By the 1970s million, mega and M were consistently being used in the powers of 1000 sense to describe HDD capacity. As HDD sizes grew the industry adopted the prefixes "G" for giga and "T" for tera denoting 1,000,000,000 and 1,000,000,000,000 bytes of HDD capacity respectively.

Likewise, the practice of using prefixes assigned to powers of 1024 within the computer industry also traces its roots to the early days of computing By the early 1970s using the prefix "K" in a powers of 1024 sense to describe memory was common within the industry. As memory sizes grew the industry adopted the prefixes "M" for mega and "G" for giga denoting 1,048,576 and 1,073,741,824 bytes of memory respectively.

Computers do not internally represent HDD or memory capacity in powers of 1024; reporting it in this manner is just a convention. Creating confusion, operating systems report HDD capacity in different ways. Most operating systems, including the Microsoft Windows operating systems use the powers of 1024 convention when reporting HDD capacity, thus an HDD offered by its manufacturer as a 1 TB drive is reported by these OSes as a 931 GB HDD. Apple's current OSes, beginning with Mac OS X 10.6 ("Snow Leopard"), use powers of 1000 when reporting HDD capacity, thereby avoiding any discrepancy between what it reports and what the manufacturer advertises.

In the case of "mega-," there is a nearly 5% difference between the powers of 1000 definition and the powers of 1024 definition. Furthermore, the difference is compounded by 2.4% with each incrementally larger prefix (gigabyte, terabyte, etc.) The discrepancy between the two conventions for measuring capacity was the subject of several class action suits against HDD manufacturers. The plaintiffs argued that the use of decimal measurements effectively misled consumers while the defendants denied any wrongdoing or liability, asserting that their marketing and advertising complied in all respects with the law and that no Class Member sustained any damages or injuries.

In December 1998, an international standards organization attempted to address these dual definitions of the conventional prefixes by proposing unique binary prefixes and prefix symbols to denote multiples of 1024, such as "mebibyte (MiB)", which exclusively denotes 220 or 1,048,576 bytes. In the over?12 years that have since elapsed, the proposal has seen little adoption by the computer industry and the conventionally prefixed forms of "byte" continue to denote slightly different values depending on context.

HDD formatting

The presentation of an HDD to its host is determined by its controller. This may differ substantially from the drive's native interface particularly in mainframes or servers.

Modern HDDs, such as SAS and SATA drives, appear at their interfaces as a contiguous set of logical blocks; typically 512 bytes long but the industry is in the process of changing to 4,096 byte logical blocks; see Advanced Format.

The process of initializing these logical blocks on the physical disk platters is called low level formatting which is usually performed at the factory and is not normally changed in the field.

High level formatting then writes the file system structures into selected logical blocks to make the remaining logical blocks available to the host OS and its applications. The operating system file system uses some of the disk space to organize files on the disk, recording their file names and the sequence of disk areas that represent the file. Examples of data structures stored on disk to retrieve files include the MS DOS file allocation table (FAT), and UNIX inodes, as well as other operating system data structures. As a consequence not all the space on a hard drive is available for user files. This file system overhead is usually less than 1% on drives larger than 100 MB.

Interface of the Hard Drive

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Hard disk drives are accessed over one of a number of bus types, including parallel ATA (P-ATA, also called IDE or EIDE), Serial ATA (SATA), SCSI, Serial Attached SCSI (SAS), and Fibre Channel. Bridge circuitry is sometimes used to connect hard disk drives to buses that they cannot communicate with natively, such as IEEE 1394, USB and SCSI.

Introduce of interface

• For the ST-506 interface, the data encoding scheme as written to the disk surface was also important. The first ST-506 disks used Modified Frequency Modulation (MFM) encoding, and transferred data at a rate of 5 megabits per second. Later controllers using 2,7 RLL (or just "RLL") encoding caused 50% more data to appear under the heads compared to one rotation of an MFM drive, increasing data storage and data transfer rate by 50%, to 7.5 megabits per second.

• Many ST-506 interface disk drives were only specified by the manufacturer to run at the 1/3 lower MFM data transfer rate compared to RLL, while other drive models (usually more expensive versions of the same drive) were specified to run at the higher RLL data transfer rate. In some cases, a drive had sufficient margin to allow the MFM specified model to run at the denser/faster RLL data transfer rate (not recommended nor guaranteed by manufacturers). Also, any RLL-certified drive could run on any MFM controller, but with 1/3 less data capacity and as much as 1/3 less data transfer rate compared to its RLL specifications.

• Enhanced Small Disk Interface (ESDI) also supported multiple data rates (ESDI disks always used 2,7 RLL, but at 10, 15 or 20 megabits per second), but this was usually negotiated automatically by the disk drive and controller; most of the time, however, 15 or 20 megabit ESDI disk drives were not downward compatible (i.e. a 15 or 20 megabit disk drive would not run on a 10 megabit controller). ESDI disk drives typically also had jumpers to set the number of sectors per track and (in some cases) sector size.

• Modern hard drives present a consistent interface to the rest of the computer, no matter what data encoding scheme is used internally. Typically a DSP in the electronics inside the hard drive takes the raw analog voltages from the read head and uses PRML and Reed–Solomon error correction to decode the sector boundaries and sector data, then sends that data out the standard interface. That DSP also watches the error rate detected by error detection and correction, and performs bad sector remapping, data collection for Self-Monitoring, Analysis, and Reporting Technology, and other internal tasks.

• SCSI originally had just one signaling frequency of 5 MHz for a maximum data rate of 5 megabytes/second over 8 parallel conductors, but later this was increased dramatically. The SCSI bus speed had no bearing on the disk's internal speed because of buffering between the SCSI bus and the disk drive's internal data bus; however, many early disk drives had very small buffers, and thus had to be reformatted to a different interleave (just like ST-506 disks) when used on slow computers, such as early Commodore Amiga, IBM PC compatibles and Apple Macintoshes.

• ATA disks have typically had no problems with interleave or data rate, due to their controller design, but many early models were incompatible with each other and could not run with two devices on the same physical cable in a master/slave setup. This was mostly remedied by the mid-1990s, when ATA's specification was standardized and the details began to be cleaned up, but still causes problems occasionally (especially with CD-ROM and DVD-ROM disks, and when mixing Ultra DMA and non-UDMA devices). Serial ATA does away with master/slave setups entirely, placing each disk on its own channel (with its own set of I/O ports) instead.

• FireWire/IEEE 1394 and USB(1.0/2.0) HDDs are external units containing generally ATA or SCSI disks with ports on the back allowing very simple and effective expansion and mobility. Most FireWire/IEEE 1394 models are able to daisy-chain in order to continue adding peripherals without requiring additional ports on the computer itself. USB however, is a point to point network and does not allow for daisy-chaining. USB hubs are used to increase the number of available ports and are used for devices that do not require charging since the current supplied by hubs is typically lower than what's available from the built-in USB ports.

Disk interface families used in personal computers

1. Historical bit serial interfaces connect a hard disk drive (HDD) to a hard disk controller (HDC) with two cables, one for control and one for data. (Each drive also has an additional cable for power, usually connecting it directly to the power supply unit). The HDC provided significant functions such as serial/parallel conversion, data separation, and track formatting, and required matching to the drive (after formatting) in order to assure reliability. Each control cable could serve two or more drives, while a dedicated (and smaller) data cable served each drive.

   • ST506 used MFM (Modified Frequency Modulation) for the data encoding method.

   • ST412 was available in either MFM or RLL (Run Length Limited) encoding variants.

   • Enhanced Small Disk Interface (ESDI) was an industry standard interface similar to ST412 supporting higher data rates between the processor and the disk drive.

2. Modern bit serial interfaces connect a hard disk drive to a host bus interface adapter (today typically integrated into the "south bridge") with one data/control cable. (As for historical bit serial interfaces above, each drive also has an additional power cable, usually direct to the power supply unit.)

   • Fibre Channel (FC), is a successor to parallel SCSI interface on enterprise market. It is a serial protocol. In disk drives usually the Fibre Channel Arbitrated Loop (FC-AL) connection topology is used. FC has much broader usage than mere disk interfaces, and it is the cornerstone of storage area networks (SANs). Recently other protocols for this field, like iSCSI and ATA over Ethernet have been developed as well. Confusingly, drives usually use copper twisted-pair cables for Fibre Channel, not fibre optics. The latter are traditionally reserved for larger devices, such as servers or disk array controllers.

   • Serial ATA (SATA). The SATA data cable has one data pair for differential transmission of data to the device, and one pair for differential receiving from the device, just like EIA-422. That requires that data be transmitted serially. Similar differential signaling system is used in RS485, LocalTalk, USB, Firewire, and differential SCSI.

   • Serial Attached SCSI (SAS). The SAS is a new generation serial communication protocol for devices designed to allow for much higher speed data transfers and is compatible with SATA. SAS uses a mechanically identical data and power connector to standard 3.5-inch SATA1/SATA2 HDDs, and many server-oriented SAS RAID controllers are also capable of addressing SATA hard drives. SAS uses serial communication instead of the parallel method found in traditional SCSI devices but still uses SCSI commands.

3. Word serial interfaces connect a hard disk drive to a host bus adapter (today typically integrated into the "south bridge") with one cable for combined data/control. (As for all bit serial interfaces above, each drive also has an additional power cable, usually direct to the power supply unit.) The earliest versions of these interfaces typically had a 8 bit parallel data transfer to/from the drive, but 16-bit versions became much more common, and there are 32 bit versions. Modern variants have serial data transfer. The word nature of data transfer makes the design of a host bus adapter significantly simpler than that of the precursor HDD controller.

   • Integrated Drive Electronics (IDE), later renamed to ATA, with the alias P-ATA ("parallel ATA") retroactively added upon introduction of the new variant Serial ATA. The original name reflected the innovative integration of HDD controller with HDD itself, which was not found in earlier disks. Moving the HDD controller from the interface card to the disk drive helped to standardize interfaces, and to reduce the cost and complexity. The 40-pin IDE/ATA connection transfers 16 bits of data at a time on the data cable. The data cable was originally 40-conductor, but later higher speed requirements for data transfer to and from the hard drive led to an "ultra DMA" mode, known as UDMA. Progressively swifter versions of this standard ultimately added the requirement for a 80-conductor variant of the same cable, where half of the conductors provides grounding necessary for enhanced high-speed signal quality by reducing cross talk. The interface for 80-conductor only has 39 pins, the missing pin acting as a key to prevent incorrect insertion of the connector to an incompatible socket, a common cause of disk and controller damage.

   • EIDE was an unofficial update (by Western Digital) to the original IDE standard, with the key improvement being the use of direct memory access (DMA) to transfer data between the disk and the computer without the involvement of the CPU, an improvement later adopted by the official ATA standards. By directly transferring data between memory and disk, DMA eliminates the need for the CPU to copy byte per byte, therefore allowing it to process other tasks while the data transfer occurs.

   • Small Computer System Interface (SCSI), originally named SASI for Shugart Associates System Interface, was an early competitor of ESDI. SCSI disks were standard on servers, workstations, Commodore Amiga, and Apple Macintosh computers through the mid-1990s, by which time most models had been transitioned to IDE (and later, SATA) family disks. Only in 2005 did the capacity of SCSI disks fall behind IDE disk technology, though the highest-performance disks are still available in SCSI and Fibre Channel only. The range limitations of the data cable allows for external SCSI devices. Originally SCSI data cables used single ended (common mode) data transmission, but server class SCSI could use differential transmission, either low voltage differential (LVD) or high voltage differential (HVD). ("Low" and "High" voltages for differential SCSI are relative to SCSI standards and do not meet the meaning of low voltage and high voltage as used in general electrical engineering contexts, as apply e.g. to statutory electrical codes; both LVD and HVD use low voltage signals (3.3 V and 5 V respectively) in general terminology.)

General interfacr as follow :

Form factor of the Hard Drive

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Mainframe and minicomputer hard disks were of widely varying dimensions, typically in free standing cabinets the size of washing machines (e.g. HP 7935 and DEC RP06 Disk Drives) or designed so that dimensions enabled placement in a 19" rack (e.g. Diablo Model 31). In 1962, IBM introduced its model 1311 disk, which used 14 inch (nominal size) platters. This became a standard size for mainframe and minicomputer drives for many years, but such large platters were never used with microprocessor-based systems.

Detail

With increasing sales of microcomputers having built in floppy-disk drives (FDDs), HDDs that would fit to the FDD mountings became desirable, and this led to the evolution of the market towards drives with certain Form factors, initially derived from the sizes of 8-inch, 5.25-inch, and 3.5-inch floppy disk drives. Smaller sizes than 3.5 inches have emerged as popular in the marketplace and/or been decided by various industry groups.

• 8 inch: 9.5 in × 4.624 in × 14.25 in (241.3 mm × 117.5 mm × 362 mm)In 1979, Shugart Associates' SA1000 was the first form factor compatible HDD, having the same dimensions and a compatible interface to the 8″ FDD.

• 5.25 inch: 5.75 in × 3.25 in × 8 in (146.1 mm × 82.55 mm × 203 mm) This smaller form factor, first used in an HDD by Seagate in 1980, was the same size as full-height 5+1?4-inch-diameter (130 mm) FDD, 3.25-inches high. This is twice as high as "half height"; i.e., 1.63 in (41.4 mm). Most desktop models of drives for optical 120 mm disks (DVD, CD) use the half height 5?″ dimension, but it fell out of fashion for HDDs. The Quantum Bigfoot HDD was the last to use it in the late 1990s, with "low-profile" (≈25 mm) and "ultra-low-profile" (≈20 mm) high versions.

• 3.5 inch: 4 in × 1 in × 5.75 in (101.6 mm × 25.4 mm × 146 mm) = 376.77344 cm3 This smaller form factor, first used in an HDD by Rodime in 1983, was the same size as the "half height" 3?″ FDD, i.e., 1.63 inches high. Today it has been largely superseded by 1-inch high "slimline" or "low-profile" versions of this form factor which is used by most desktop HDDs.

• 2.5 inch: 2.75 in × 0.275–0.59 in × 3.945 in (69.85 mm × 7–15 mm × 100 mm) = 48.895–104.775 cm3 This smaller form factor was introduced by PrairieTek in 1988; there is no corresponding FDD. It is widely used today for solid-state drives and for hard-disk drives in mobile devices (laptops, music players, etc.) and as of 2008 replacing 3.5 inch enterprise-class drives. It is also used in the Playstation 3 and Xbox 360[citation needed] video game consoles. Today, the dominant height of this form factor is 9.5 mm for laptop drives (usually having two platters inside), but higher capacity drives have a height of 12.5 mm (usually having three platters). Enterprise-class drives can have a height up to 15 mm. Seagate has released a 7mm drive aimed at entry level laptops and high end netbooks in December 2009.

• 1.8 inch: 54 mm × 8 mm × 71 mm = 30.672 cm3 This form factor, originally introduced by Integral Peripherals in 1993, has evolved into the ATA-7 LIF with dimensions as stated. It was increasingly used in digital audio players and subnotebooks, but is rarely used today. An original variant exists for 2–5GB sized HDDs that fit directly into a PC card expansion slot. These became popular for their use in iPods and other HDD based MP3 players.

• 1 inch: 42.8 mm × 5 mm × 36.4 mm This form factor was introduced in 1999 as IBM's Microdrive to fit inside a CF Type II slot. Samsung calls the same form factor "1.3 inch" drive in its product literature.

• 0.85 inch: 24 mm × 5 mm × 32 mm Toshiba announced this form factor in January 2004 for use in mobile phones and similar applications, including SD/MMC slot compatible HDDs optimized for video storage on 4G handsets. Toshiba currently sells a 4 GB (MK4001MTD) and 8 GB (MK8003MTD) version and holds the Guinness World Record for the smallest hard disk drive.

By 2009 all manufacturers had discontinued the development of new products for the 1.3-inch, 1-inch and 0.85-inch form factors due to falling prices of flash memory, which is slightly more stable and resistant to damage from impact and/or dropping.

The inch-based nickname of all these form factors usually do not indicate any actual product dimension (which are specified in millimeters for more recent form factors), but just roughly indicate a size relative to disk diameters, in the interest of historic continuity.

Current hard disk form factors

Obsolete hard disk form factors