Hardware
of Laptop
Miniaturization: a comparison of a desktop computer motherboard (ATXform factor) to a motherboard from a 13" laptop (2008 unibody Macbook)
Inner view of a Sony VAIO laptop
The basic components of laptops function identically to their desktop counterparts. Traditionally they were miniaturized and adapted to mobile use, although desktop systems increasingly use the same smaller, lower-power parts which were originally developed for mobile use. The design restrictions on power, size, and cooling of laptops limit the maximum performance of laptop parts compared to that of desktop components, although that difference has increasingly narrowed.
In general, laptop components are not intended to be replaceable or upgradable, with the exception of components which can be detached, such as a battery or CD/CDR/DVD drive. This restriction is one of the major differences between laptops and desktop computers, because the large "tower" cases used in desktop computers are designed so that new motherboards, hard disks, sound cards, RAM, and other components can be added. In a very compact laptop, such as laplets, there may be no upgradeable components at all.
Intel, Asus, Compal, Quanta, and some other laptop manufacturers have created the Common Building Block standard for laptop parts to address some of the inefficiencies caused by the lack of standards and inability to upgrade components.The following sections summarizes the differences and distinguishing features of laptop components in comparison to desktop personal computer parts.
Display
Most modern laptops feature a 13 inches (33 cm) or larger color active matrix display based on LED lighting with resolutions of 1280×800 (16:10) or 1366×768 (16:9) pixels and above. Models with LED-based lighting offer lesser power consumption, and often increased brightness. Netbooks with a 10 inches (25 cm) or smaller screen typically use a resolution of 1024×600, while netbooks and subnotebooks with a 11.6 inches (29 cm) or 12 inches (30 cm) screen use standard notebook resolutions.
Having a higher resolution display allows more items to fit onscreen at a time, improving the user's ability to multitask, although at the higher resolutions on smaller screens, the resolution may only serve to display sharper graphics and text rather than increasing the usable area. Since the introduction of the MacBook Pro with Retina display in 2012, there has been an increase in the availability of very-high resolution (1920×1080 and higher) displays, even in relatively small systems, and in typical 15-inch screens resolutions as high as 3200×1800 are available. External displays can be connected to most laptops, and models with a Mini DisplayPort can handle up to three.
Central processing unit
A laptop's central processing unit (CPU) has advanced power-saving features and produces less heat than one intended purely for desktop use. Typically, laptop CPUs have two processor cores, although 4-core models are also available. For low price and mainstream performance, there is no longer a significant performance difference between laptop and desktop CPUs, but at the high end, the fastest 4-to-8-core desktop CPUs still substantially outperform the fastest 4-core laptop processors, at the expense of massively higher power consumption and heat generation; the fastest laptop processors top out at 56 watts of heat, while the fastest desktop processors top out at 150 watts.
There have been a wide range of CPUs designed for laptops available from both Intel, AMD, and other manufacturers. On non-x86 architectures, Motorola and IBM produced the chips for the former PowerPC-based Apple laptops (iBook and PowerBook). Many laptops have removable CPUs, although this has become less common in the past few years as the trend has been towards thinner and lighter models. In other laptops the CPU is soldered on the motherboard and is non-replaceable; this is nearly universal in ultrabooks.
In the past, some laptops have used a desktop processor instead of the laptop version and have had high performance gains at the cost of greater weight, heat, and limited battery life, but the practice was largely extinct as of 2013. Unlike their desktop counterparts, laptop CPUs are nearly impossible to overclock. A thermal operating mode of laptops is very close to its limits and there is almost no headroom for an overclocking–related operating temperature increase. The possibility of improving a cooling system of a laptop to allow overclocking is extremely difficult to implement.
Graphical processing unit
On most laptops a graphical processing unit (GPU) is integrated into the CPU to conserve power and space. This was introduced by Intel with the Core i-series of mobile processors in 2010, and similar accelerated processing unit (APU) processors by AMD later that year. Prior to that, lower-end machines tended to use graphics processors integrated into the system chipset, while higher end machines had a separate graphics processor.
In the past, laptops lacking a separate graphics processor were limited in their utility for gaming and professional applications involving 3D graphics, but the capabilities of CPU-integrated graphics have converged with the low-end of dedicated graphics processors in the past few years. Higher-end laptops intended for gaming or professional 3D work still come with dedicated, and in some cases even dual, graphics processors on the motherboard or as an internal expansion card. Since 2011, these almost always involve switchable graphics so that when there is no demand for the higher performance dedicated graphics processor, the more power-efficient integrated graphics processor will be used. Nvidia Optimus is an example of this sort of system of switchable graphics.
Memory
Most laptops use SO-DIMM (small outline dual in-line memory module) memory modules, as they are about half the size of desktop DIMMs. They are sometimes accessible from the bottom of the laptop for ease of upgrading, or placed in locations not intended for user replacement. Most laptops have two memory slots, although some of the lowest-end models will have only one, and some high end models (usually mobile engineering workstations and a few high-end models intended for gaming) have four slots.
Most mid-range laptops are factory equipped with 4–6 GB of RAM. Netbooks are commonly equipped with only 1–2 GB of RAM and are generally only expandable to 2 GB, if at all. Laptops may have memory soldered to the motherboard to conserve space, which allows the laptop to have a thinner chassis design. Soldered memory cannot be easily upgraded.
Internal storage
Traditionally, laptops had a hard disk drive (HDD) as a main non-volatile storage, but these proved inefficient for use in mobile devices due to high power consumption, heat production, and a presence of moving parts, which can cause damage to both the drive itself and the data stored when a laptop is unstable physically, e.g. during its use while transporting it or after its accidental drop. With the advent of flash memory technology, most mid- to high-end laptops opted for more compact, power efficient, and fast solid-state drives (SSD), which eliminated the hazard of drive and data corruption caused by a laptop's physical impacts.
Most laptops use 2.5-inch drives, which are a smaller version of a 3.5-inch desktop drive form factor. 2.5-inch HDDs are more compact, power efficient, and produce less heat, while at the same time have a smaller capacity and a slower data transfer rate. Some very compact laptops support even smaller 1.8-inch HDDs. For SSDs, however, these miniaturization-related trade-offs are nonexistent, because SSDs were designed to have a very small footprint. SSDs feature a traditional 2.5- or 1.8-inch or a laptop-specific mSATA or M.2 card's form factor. SSDs have a higher data transfer rate, lower power consumption, lower failure rate, and a larger capacity compared to HDDs. However, HDDs have a significantly lower cost.
Most laptops can contain a single 2.5-inch drive, but a small number of laptops with a screen wider than 15 inches can house two drives. Some laptops support a hybrid mode, combining a 2.5-inch drive, typically a spacious HDD for data, with an mSATA or M.2 SDD drive, typically having less capacity, but a significantly faster read/write speed. The operating system partition would be located on the SSD to increase laptop I/O performance. Another way to increase performance is to use a smaller SSD of 16-32 GB as a cache drive with a compatible OS. Some laptops may have very limited drive upgradeability when the SSD used has a non-standard shape or requires a proprietary daughter card.
Some laptops have very limited space on the installed SSD, instead relying on availability of cloud storage services for storing of user data; Chromebooks are a prominent example of this approach. A variety of external HDDs or NAS data storage servers with support of RAID technology can be attached to virtually any laptop over such interfaces as USB, FireWire, eSATA, or Thunderbolt, or over a wired or wireless network to further increase space for the storage of data. Many laptops also incorporate a card reader which allows for use of memory cards, such as those used for digital cameras, which are typically SD or microSD cards. This enables users to download digital pictures from an SD card onto a laptop, thus enabling them to delete the SD card's contents to free up space for taking new pictures.
Removable media drive
Optical disc drives capable of playing CD-ROMs, compact discs (CD), DVDs, and in some cases, Blu-ray Discs (BD), were nearly universal on full-sized models by the early 2010s. A disc drive remains fairly common in laptops with a screen wider than 15 inches (38 cm), although the trend towards thinner and lighter machines is gradually eliminating these drives and players; these drives are uncommon in compact laptops, such as subnotebooks and netbooks. Laptop optical drives tend to follow a standard form factor, and usually have a standard mSATA connector. It is often possible to replace an optical drive with a newer model. In certain laptop models there is a possibility to replace an optical drive with a second hard drive, using a caddy that fills the extra space the optical drive would have occupied.
Inputs
Closeup of a touchpad on an Acerlaptop
An alphanumeric keyboard is used to enter text and data and make other commands (e.g., function keys). A touchpad (also called a trackpad), a pointing stick, or both, are used to control the position of the cursor on the screen, and an integrated keyboard is used for typing. An external keyboard and mouse may be connected using a USB port or wirelessly, via Bluetooth or similar technology.
With the advent of ultrabooks and support of touch input on screens by 2010-era operating systems, such as Windows 8.1, multitouch touchscreendisplays are used in many models. Some models have webcams and microphones, which can be used to communicate with other people with both moving images and sound, via Skype, Google Chat and similar software. Laptops typically have USB ports and a microphone jack, for use with an external mic. Some laptops have a card reader for reading digital camera SD cards.
Input/output (I/O) ports
On a typical laptop there are several USB ports, an external monitor port (VGA, DVI, HDMI or Mini DisplayPort), an audio in/out port (often in form of a single socket) is common. It is possible to connect up to three external displays to a 2014-era laptop via a single Mini DisplayPort, utilizing multi-stream transport technology.Apple, in a 2015 version of its MacBook, transitioned from a number of different I/O ports to a single USB-C port.
This port can be used both for charging and connecting a variety of devices through the use of aftermarket adapters. Google, with its updated version of Chromebook Pixel, shows a similar transition trend towards USB-C, although keeping older USB Type-A ports for a better compatibility with older devices.[45] Although being common until the end of the 2000s decade, Ethernet network port are rarely found on modern laptops, due to widespread use of wireless networking, such as Wi-Fi. Legacy ports such as a PS/2 keyboard/mouse port, serial port, parallel port, or Firewire are provided on some models, but they are increasingly rare. On Apple's systems, and on a handful of other laptops, there are also Thunderbolt ports, but Thunderbolt 3 uses USB-C. Laptops typically have a headphone jack, so that the user can connect external headphones or amplified speaker systems for listening to music or other audio.
Expansion cards
In the past, a PC Card (formerly PCMCIA) or ExpressCard slot for expansion was often present on laptops to allow adding and removing functionality, even when the laptop is powered on; these are becoming increasingly rare since the introduction of USB 3.0. Some internal subsystems such as: Ethernet, Wi-Fi, or a wireless cellular modem can be implemented as replaceable internal expansion cards, usually accessible under an access cover on the bottom of the laptop. The standard for such cards is PCI Express, which comes in both mini and even smaller M.2 sizes. In newer laptops, it is not uncommon to also see Micro SATA (mSATA) functionality on PCI Express Mini or M.2 card slots allowing the use of those slots for SATA-based solid state drives.
Battery and power supply
Almost all laptops use smart batteries
2016-era laptops use lithium ion batteries, with some thinner models using the flatter lithium polymer technology. These two technologies have largely replaced the older nickel metal-hydride batteries. Battery life is highly variable by model and workload, and can range from one hour to nearly a day.
A battery's performance gradually decreases over time; substantial reduction in capacity is typically evident after one to three years of regular use, depending on the charging and discharging pattern and the design of the battery. Innovations in laptops and batteries have seen situations in which the battery can provide up to 24 hours of continued operation, assuming average power consumption levels. An example is the HP EliteBook 6930p when used with its ultra-capacity battery.
A laptop's battery is charged using an external power supply which is plugged into a wall outlet. The power supply outputs a DC voltage typically in the range of 7.2—24 volts. The power supply is usually external, and connected to the laptop through a DC connector cable. In most cases, it can charge the battery and power the laptop simultaneously.
When the battery is fully charged, the laptop continues to run on power supplied by the external power supply, avoiding battery use. The battery charges in a shorter period of time if laptop is turned off or sleeping. The charger typically adds about 400 grams (0.88 lb) to the overall transporting weight of a laptop, although some models are substantially heavier or lighter. Most 2016-era laptops use a smart battery, a rechargeable battery pack with a built-in battery management system (BMS). The smart battery can internally measure voltage and current, and deduce charge level and SoH (State of Health) parameters, indicating the state of the cells.
Cooling
Waste heat from operation is difficult to remove in the compact internal space of a laptop. Early laptops used heat sinks placed directly on the components to be cooled, but when these hot components are deep inside the device, a large space-wasting air duct is needed to exhaust the heat. Modern laptops instead rely on heat pipes to rapidly move waste heat towards the edges of the device, to allow for a much smaller and compact fan and heat sink cooling system. Waste heat is usually exhausted away from the device operator towards the rear or sides of the device.
Multiple air intake paths are used since some intakes can be blocked, such as when the device is placed on a soft conforming surface like a chair cushion. It is believed that some designs with metal cases, like Apple's aluminum MacBook Pro and MacBook Air, also employ the case of the machine as a heat sink, allowing it to supplement cooling by dissipating heat out of the device core. Secondary device temperature monitoring may reduce performance or trigger an emergency shutdown if it is unable to dissipate heat, such as if the laptop were to be left running and placed inside a carrying case. Aftermarket cooling pads with external fans can be used with laptops to reduce operating temperatures.
Docking station
Docking station and laptop
A docking station (sometimes referred to simply as a dock) is a laptop accessory that contains multiple ports, and in some cases expansion slots or bays for fixed or removable drives. A laptop connects and disconnects to a docking station, typically through a single large proprietary connector.
A docking station is an especially popular laptop accessory in a corporate computing environment, due to a possibility of a docking station to transform a laptop into a full-featured desktop replacement, yet allowing for its easy release. This ability can be advantageous to "road warrior" employees who have to travel frequently for work, and yet who also come into the office. If more ports are needed, or their position on a laptop is inconvenient, one can use a cheaper passive device known as a port replicator. These devices mate to the connectors on the laptop, such as through USB or FireWire.
Charging trolleys
Laptop charging trolleys, also known as laptop trolleys or laptop carts, are mobile storage containers to charge multiple laptops, netbooks, and tablet computers at the same time. The trolleys are used in schools that have replaced their traditional static computer labs suites of desktop equipped with "tower" computers, but do not have enough plug sockets in an individual classroom to charge all of the devices. The trolleys can be wheeled between rooms and classrooms so that all students and teachers in a particular building can access fully charged IT equipment.
Laptop charging trolleys are also used to deter and protect against opportunistic and organized theft. Schools, especially those with open plandesigns, are often prime targets for thieves who steal high-value items. Laptops, netbooks, and tablets are among the highest–value portable items in a school. Moreover, laptops can easily be concealed under clothing and stolen from buildings. Many types of laptop–charging trolleys are designed and constructed to protect against theft. They are generally made out of steel, and the laptops remain locked up while not in use. Although the trolleys can be moved between areas from one classroom to another, they can often be mounted or locked to the floor or walls to prevent thieves from stealing the laptops, especially overnight.
Solar panels
In some laptops, solar panels are able to generate enough solar power for the laptop to operate. The One Laptop Per Child Initiative released the OLPC XO-1 laptop which was tested and successfully operated by use of solar panels. Presently, they are designing a OLPC XO-3 laptop with these features. The OLPC XO-3 can operate with 2 watts of electricity because its renewable energy resources generate a total of 4 watts. Samsung has also designed the NC215S solar–powered notebook that will be sold commercially in the U.S. market.
Accessories
A common accessory for laptops is a laptop sleeve, laptop skin, or laptop case, which provides a degree of protection from scratches. Sleeves, which are distinguished by being relatively thin and flexible, are most commonly made of neoprene, with sturdier ones made of low-resilience polyurethane. Some laptop sleeves are wrapped in ballistic nylon to provide some measure of waterproofing.
Bulkier and sturdier cases can be made of metal with polyurethane padding inside, and may have locks for added security. Metal, padded cases also offer protection against impacts and drops. Another common accessory is a laptop cooler, a device which helps lower the internal temperature of the laptop either actively or passively. A common active method involves using electric fans to draw heat away from the laptop, while a passive method might involve propping the laptop up on some type of pad so it can receive more air flow. Some stores sell laptop pads which enable a reclining person on a bed to use a laptop.
Obsolete features
A modem PCMCIA card on an old ThinkPad
Features that certain early models of laptops used to have that are not available in most 2017 laptops include:
- Reset ("cold restart") button in a hole (needed a thin metal tool to press)
- Instant power off button in a hole (needed a thin metal tool to press)
- Integrated charger or power adapter inside the laptop
- Floppy disk drive
- Serial port
- Parallel port
- Modem
- Shared PS/2 input device port
- VHS or 8mm VCR
- IrDA
- S-video port
- PC Card / PCMCIA slot
- ExpressCard slot
- A common accessory for laptops is a laptop sleeve, laptop skin, or laptop case, which provides a degree of protection from scratches. Sleeves, which are distinguished by being relatively thin and flexible, are most commonly made of neoprene, with sturdier ones made of low-resilience polyurethane. Some laptop sleeves are wrapped in ballistic nylon to provide some measure of waterproofing.
No comments