Types of Portables
Portable computers are classified according to size and function. Today there are three basic types of portable computers: laptop, notebook, and small optional.
The first “portable” computers were often called “luggables.” The size of a portable sewing machine, they tipped the scales at 30 pounds. Equipped with a small CRT (cathode ray tube) display, they were actually a traditional PC in a slightly smaller case.
The real change in portable computers came with the advent of flat panel displays, allowing portables to take on the now familiar slim design. Laptops are usually offered for most of the features of a full PC but for the bulky version, with a folding flat panel display and integrated keyboard. Notebooks are often lean devices that lack the full range of storage as part of the general configuration. A particular set of products offering a subset of features, including PDAs, e-mail, schedule tracking, contact records, and limited note-taking and web browsing, are beyond the scope of this chapter.
Advances in battery technology and functional, large screens, liquid crystal displays (LCDs), with the advent of the first truly portable computers, referred to as laptops, were produced in the late 1980s. These units featured integrated AT compatible computer boards, including I / O (input / output) and video controller functions. Laptops, as mentioned, usually include a folding LCD display and a built-in keyboard and pointing device. They also use an external power supply and a removable, battery. Today laptops are quite large (2 GB or more) hard drives, a CD-ROM drive (or DVD drive), and a floppy disk drive (often the latter two are interchangeable plug-ins).
Laptops originally appeared on the market, they were the smallest portable computers made. Today, they are high-end machines that offer features and performance comparable to a desktop system.
Advances in integrated circuits (IC) technology have allowed the size of computer components to be reduced even further and in the early to mid-1980s, notebook computers were born. The notebooks are roughly 8.75 inches thick × 11 inches wide × 2.25 inches thick, and designers are working to further reduce the size and power consumption of these units. The size reduction, however, comes at a price, and notebooks generally display smaller and less capable than laptops and have keyboards. A wide variety of specialty items designed to overcome some of the notebook’s shortcomings have appeared on the market. A docking port is one such item.
(Also known as docking station) Docking port can be inserted an entire notebook computer in which there are special cases. This notebook allows connecting to desktop I / O devices such as full size keyboards, CRT monitors, and network connections. At a minimum, a docking station provides an alternating current (AC) power source for the notebook. Docking stations are highly proprietary items created for use with specific computer models. They are only working for the user who wants to maintain a single computer system and avoid the need for the transfer of information between the two systems. With a docking port and a well-equipped notebook computer, it is possible to have the best of both worlds.
This device has a docking port for pointing, a portable computer with a full-size keyboard, and is not required to monitor. Most portables have standard connectors for these peripherals. However, be aware that you may have to connect devices before booting the computer.
Sub note book (Palmtop) Computers
Notebook computers, even small computers, also known as palmtops or handhelds, are all note books. These smaller systems are 7 inches wide × 4 inches deep × 1 inch high. Due to their size, they are rather limited in function. Keyboards, for example, are too small to allow touch typing. With the reduction in notebook costs and weight, palmtops have lost market share and popularity.
In order to provide laptop and notebook computers with the same expandability associated with desktop computers, PCMCIA (International Association of Personal Computer Memory Cards) has several standards for credit card-sized expansion boards that fit into smaller slots on these smaller machines. Established. These expansion boards are now commonly referred to as PC cards. PCMCIA standards have revolutionized mobile personal computers, providing memory expansion cards, network interface cards (NICs) with the ability to connect, SCSI (small computer system interfaces) devices, communications hardware (for example, modems and Fax), and many other laptop and notebook computer users that devices that were not previously available.
Compatibility problems were encountered with the development of PC cards for portable computers. To overcome these inconsistencies, PCMCIA standards were created. The following table outlines the four PCMCIA types and their guidelines.
Type standard description
Type I This basic computer-card standard is now known as the Type I standard. These slots only work with memory expansion cards. Type I cards are 3.3 mm thick.
Type II Type II cards support most types of expansion devices (such as communications hardware) or network adapters. Type II can accommodate cards that are 5 mm thick.
Type III Type III slots are primarily for computers with removable hard disk drives. This standard was introduced in 1992. They are 10.5 mm thick; However, they are compatible with Type I and Type II cards.
Type IV slots are used with hard disk drives that are thicker than the 10.5 mm Type III slot.
The PC card itself is usually sealed in a thin metal case. One end PC card. Interfaces for (68 small pinholes) are included, the other end may include an input line, a network, or a ynder to any other external device.
The PC card is part of the Plug and Play standard, which means it allows you to connect components without first shutting down or rebooting the computer. In short, PC cards (because they have no need) are not advertised with jumper settings but with software.
Portable Computer Hardware
A portable computer has many components similar to a desktop system, some components are very different. The main difference between a portable system and a desktop system is the display screen.
Portable computers have a flat LCD screen that is about .5 inches thick. Performance is generally the most expensive component in a portable system. Often it is more economical to replace the entire computer by replacing the screen. An LCD display cannot resize pixels on an LCD panel because it is designed to operate at a specific resolution. On a desktop system, by contrast, signal output from the video adapter can change the resolution on the monitor, thereby changing the number of pixels on the screen. An LCD panel should be thought of as a grid that rejects a specific resolution. The transistors control the color that is displayed by each pixel. The two major types of LCD displays used in portable systems today (dual-scan and active matrix) are defined by their arrangement of transistors.
(Also known as a passive matrix display) The dual scan display screen consists of transistors running under the X and Y axis. The number of transistors determines the resolution of the screen. The two transistors that intersect each pixel on the screen on the X and Y axis control.
If a transistor fails, the entire line of pixels is disabled, leaving a black line across the screen. There is no way to rectify this problem except for the performance space. Duration Dual-scan processor refresh rate is derived from the fact that a small speed which redraws half of the screen at a time.
They become dimmer because dual-scan displays are considered inferior to active matrix screens. For this reason, portable computers are becoming rare with this technology. They work by generating their own light rather than modifying the properties of reflected light. They also suffer from ghost images, and it is difficult for two people to see the screen at the same time because these displays cannot be seen well from an angle. The standard size of this type of screen is 10.5 inches (measured diagonally) with a resolution of 640 × 480. The new systems are available with a resolution of 800 × 600 that displays 12.1 inches and larger.
Active matrix displays are also known as TFTs (thin film transistors). They not only have a transistor for every pixel on the screen from the edges because they are different from double scan screens. Electrodes apply voltages at the perimeter of the grid to address each pixel individually.
Each pixel has its own light and proper color, operating individually, producing a much brighter and more vivid picture result. Creating light provides a wider viewing angle allowing for more than one viewer to see the screen at a time rather than shuffling the reflection. Refreshments are fast and the performance lacks the fuzziness associated with dual scan systems.
Naturally, the price of having only 1400 to 480,000 transistors (on an 800 × 600 screen) makes active matrix screens more expensive. It also requires a much faster and more power drains and batteries. Failure of a transistor causes ‘dead pixels’ person, but it is far less noticeable than the black line caused by a transistor failure of the dual-scan screen.
Large screens and high resolutions mimicking desktop models have become standard on high-end laptops. Many portable systems even today include PCI (peripheral component interconnect) bus video adapters. These screens came very close to the quality of a desktop display, but there is some lack of fine control available on fixed units.
The resolution of an LCD display is determined as much by the screen hardware as by the drivers and amount of installed video memory. Some machines with less robust screens achieve resolutions of 600 × (even more) × 1024 by using a virtual screen. This is a memory swapping technique that displays the portion that fits the actual screen into a 640 × 480 window, while a larger display is held in video memory. The cursor can be used to “pan” the image so that the viewable desktop is within the physical boundaries of the actual display.
As in regular desktop systems, color depth is affected by video memory. To operate any LCD display in 16 bit or 24 bit color mode you must have sufficient video memory available. The portable usually has video adapter hardware installed on the motherboard, which permanently makes an upgrade of performance almost impossible features. Most portables allow connection to an external monitor to enhance video capabilities.
LCD technology is not limited to portable. They are quite expensive, although large, flat panel LCD type displays are now available for desktop computers. (For more information, see “Display Systems,” chapter.)
Manufacturers of computer CPUs (central processing units) spend a great deal of time and effort on designing chips specifically for the portable market. In desktop systems, cooling fans placed inside the case dissipate CPU heat. There is no place for this solution in a portable system, so manufacturers have addressed this problem in the packaging of the chip itself.
Chip maker Intel’s solution to size and heat problems is the tape carrier package. This method of packaging reduces the size, power consumption, and heat generated by the chip. A Pentium tape carrier is smaller and lighter than the pin grid array (PGA) used in desktop systems mounted on a motherboard using packaging. The PGA has reduced 29 mm, approximately 1 mm thickness, and weight to at least 1 gram from 49 mm square 55 grams.
The tape carrier packaging processor tape is bonded to a piece of polyamide film which is like a photo film, using automatic bonding (TAB). This is the same process used to provide electrical connections to LCD panels. The film (called tape) is laminated with etched copper foil to form the motherboard processor that is connected. When the leads are formed, they are bonded to the gold processor chip itself plated to protect them against corrosion, and then the entire assembly is coated with a protective resin.
After being tested, the tape is cut to the appropriate size and ends folded into a “Fudge Wing” shape that allows the leads to be soldered to the motherboard while the processor is suspended slightly above it. Have been. A thermally conductive paste is delivered between the processor chip and the motherboard, allowing it to be dissipated through a sink on the underside of the motherboard, keeping it away from the heat soldered connection. Of course, they generally cannot be upgraded because tape carrier packaging processors are soldered to the motherboard.
Some manufacturers sometimes use standard PGA processors, with fans. Apart from having a very short battery life, these systems can be very hot to the touch at ease. Always check the exact model of processor that is used in the processing speed, not just in a system you intend to buy. You may want to purchase a non-tape carrier packaging processor for the aforementioned reasons.
The Mobile Pentium has operated at 3.3 volts since the days of the original 75 MHz chip, but has to maintain a 3.3 volt interface with newer and faster model motherboards, reducing voltage to only 2.9 volts for internal operation. It uses as little as 60 percent of the power of a desktop system that translates into a processor.
As with desktop systems, adding memory is one of the most common upgrades for portable computers. Unlike desktop computers that offer only three basic types of slots for additional RAM (random access memory), there are dozens of different memory chip configurations designed to squeeze memory upgrades into smaller cases of portable systems.
Some look a lot like portable PC cards that use memory cartridges, but they plug into a dedicated IC memory socket. Others use boards (single inline memory modules) and DIMMs (dual inline memory modules) like extender sims. In any case, it is recommended that you install the memory module only in the configuration prepared for your system, and only in the recommended configuration from the manufacturer. A number of companies manufacture upgrade modules for dozens of systems because this is necessary, however, does not limit you to products made by the manufacturer of your system.
Portable computers and desktops use the same types of dynamic RAM (DRAM) and static RAM (SRAM) as, thanks to advances in thermal management, today’s high-end portable systems typically include SRAM cache memory Huh .
Hard Disk Drives
Except for its size and packaging, portable hard disk drive technology is similar to desktop. EIDE (Enhanced Integrated Drive Electronics) drives are standard in portable computers with the exception of Macintosh computers, which uses SCSI. Internal hard drives, depending on the size of the system, typically use 12.5 mm or 19 mm long, and 2.5 inch platters. As with memory modules, hard drives are also mounted in the system by a little different manufacturers, this upgrade can cause compatibility problems.
Some manufacturers use a caddy to hold the drive and make connections to the system. This makes simple upgrades as inserting a new hard disk drive into the caddy and then mounting it in the system. In other systems it requires the purchase of a specially designed drive complete with proper connections made. Replacing hard drives can be significantly easier in many portable systems than their desktop counterparts.
The result is that many users can share the same machine only by snapping into their own hard drive. However, laptops are special devices, any servicing beyond the battery, hard drive, and memory as usually left to the experts or the manufacturer.
Determines the upgradability of a system for the support provided by the system’s BIOS (Basic Input / Output System). Older systems, especially those built before 1995, may offer only limited drive size options. BIOS chips created before EIDE hard disk drives become standard can support a maximum hard drive size of 528 MB. A flash BIOS upgrade may be available for your system to provide additional drives. Another option for expanding hard drive space is PC card hard drive. The device fits into a Type III PC card slot and can provide as much as 1-2 GB of additional space. External drives are also available and a PC card SCSI host or special parallel port drive interface you can use any size SCSI drive you choose without being limited by your system’s BIOS. Can be connected using
Portable systems are now equipped with other types of storage media that can provide access to large amounts of data. CD-ROM and ZIP drives are available now, as well as standard floppy disk drives. As desktop counterparts only, CD-ROM is becoming standard on portables.
Swappable drive bays are increasing in popularity. This product allows the user to make a switch from several types of components in the unit. For example, when traveling you will not need a floppy disk drive, you can insert an extra battery.
Portable keyboards are integrated into the one-piece unit and are therefore very difficult to repair or replace. Unfortunately, the keypad is almost always the first component to fail in a portable. Keyboard functionality and durability should be an important concern when purchasing a portable system.
Today’s portable keyboards, thanks to the big screen found on most systems, are approaching the size and functionality of desktop systems. This has become more space for manufacturers to use in the overall design.
Today’s portable computers come with built-in pointing devices. Most of these gesture devices are of three types: trackball, trackpoint, or track pad.
Trackball .. This small ball (about 0.5 inch in diameter) is partially embedded in the keyboard below the space bar. The user’s fingers manipulate the ball. These devices are accurate and useful, but they are unpopular because of their tendency to collect dirt and dust, which dramatically reduces performance.
Track point. IBM has developed trackpoint, which many manufacturers have installed in their systems. It has a small, rubberized button (about 0.25 inch in diameter) located on the keyboard B top and G and H bottom. It nudges the user in any direction (like a smaller version of a joystick) to move the cursor around the screen. No need to leave the keyboard to manipulate the trackpoint in the hands of the user because it is convenient.
Track pad .. (also known as touchpad) Trackpad is the three most recent development. It is an electromagnetically sensitive pad measuring approximately 1 inch × 2 inch located in the keyboard below the spacebar. It responds to the movement of a finger across its surface to move the cursor. Tapping the pad (though buttons are also provided) simulates mouse clicks. This is a truly innovative device, but tends to be overly sensitive to accidental touches and taps. It is also sensitive to moisture, so moist fingers may cause unexpected exposure.
In addition to portable USB (Universal Serial Bus) technology it has been made very easy to add new devices or share them with other computers like the owner’s desktop machine. The hot swap capability, coupled with the wide range of products (from printers and scanners to zip drives and modems), makes it a must-have for any new portable. Also keep in mind that there are PCMCIA USB cards on the market that can add functionality to older machines. (“Expansion Buses, Cables, and Connectors,” for more information, see chapter.)
A great deal of technology has been developed to extend battery life and improve power management in portable systems. However, battery life is still one of the most important complaints about portable systems. Energy management and the battery itself has improved dramatically over the years, however, the need for power to run faster processors and peripherals has increased leaving only battery life. Actual battery life depends more on how computers are used as it does on power management technology. Simply put, more you ask the computer to do less battery life. Today, battery life is still an issue with portable system users. Most systems use one of three types of batteries.
Nickel Cadmium Batteries
The oldest of the three technologies, nickel cadmium (NiCad) batteries are rarely used today. They have a short life and are sensitive to improper charging and discharging. Being charged, the NiCad batteries hold a charge very well. How ever, their lives can be severely shortened before recharging if they are overcharged or if they are not fully discharged.
Nickel Metal Hydride Batteries
Nickel Metal Hydride (NiMH) batteries have a longer life (about 50 percent longer) than NiCad batteries and are sensitive to improper charging and discharge. They are also more expensive than NiCad batteries and do not hold a charge as well when not used. They usually cannot be rested as well at times. They are, however, the most portable systems, especially those used at the lower end of the market.
Lithium Ion Batteries
Lithium-ion batteries hold a charge well when in use, and last longer than the other two types of batteries, cannot be overcharged. They are also skilled in handling the heavy duty power requirements of today’s high end portables. They are the most expensive of the three battery technologies, as lithium-ion batteries are typically found only in high-end systems. Unfortunately, these batteries can only be used in systems designed specifically for them.
Never install a lithium-ion battery in a system designed for NiCad or NiMH batteries. Doing so could result in a fire.
Buying a system with a lithium-ion battery does not necessarily ensure a longer battery life. It is more powerful because some manufacturers were giving the same performance as a NiCad or NiMH battery, taking the opportunity to shrink the battery, thereby saving some space inside the computer.
Battery technology has lagged behind almost all other advances of portable systems. Two-hour battery life is considered very good, even when the power-saving features of a system are used. Some manufacturers are designing systems that hold two batteries to try to overcome this limitation.
A fourth type of battery technology lithium polymer has been in development for many years, but it has not yet appeared on the market. Lithium polymer batteries can be formed into thin, flat sheets and installed behind the LCD panel. They provide about 40 percent more battery life while adding far less weight to the system.
All types of batteries work best if they are fully discharged before recharging. Even lithium-ion batteries perform better and they are discharged before being rested, so last longer. You can also charge the batteries in the refrigerator to help them keep their charges longer for the store.
Proper Battery Disposal
Many people give any idea to discarding the finished battery in the nearest garbage container, but you should take a more professional approach. Batteries contain hazardous and environmentally harmful materials. And make sure to check your company policy and recommendations with the manufacturer before disposing of any battery. Failure to do so is both an invitation to poor practice and a fix.
Some components in a computer system do not need to run continuously. The purpose of power management is to conserve battery life by shutting down these components when they are not needed.
Most portable computers include power saving mode that suspend the operation of the system when the computers are not in use. Different manufacturers have different names for their power saver modes as suspended, hibernate, or protection, but they all typically refer to two different states of power protection: the RAM of a state system continues to power, And others do not.
Generally, suspended mode almost shuts down the entire system after a certain period of inactivity. However, electricity is being supplied to Ram, and this system can be reawakened almost immediately.
Hibernate mode writes all the memory contents to a particular swap file and then the system shuts down. If reactivated, the file memory is read back. It takes a little longer to reactivate hibernate mode than suspend mode, but it conserves more battery life. In some systems, the swap file used for hibernate mode is located in a special partition of the hard drive. If it is inadvertently destroyed, it may require a special utility from the manufacturer to rebuild it.
The document power management policy, jointly developed by Intel and Microsoft, the Advanced Power Management (APM) standard, has been for the most part responsible for defining the interface (interaction) between the driver and the operating system. This interface is usually implemented in the system BIOS.
Another standard currently under development by Intel, Microsoft, and Toshiba is called Advanced Configuration and Power Interface (ACPI). The power management functions under the control of this standard operating system have been created. Development of power management techniques makes it difficult for BIOS to maintain complex information states required to run more advanced tasks. Placing power management under the control of the operating system allows applications to interact with the operating system to tell which of its activities are important and can wait until the next time that the hard disk drive is active.
Summarize the main elements of this lesson on the following points:
- Portable computers are classified as laptops, notebooks, or palmtops.
- PC cards provide expandability to portable computers.
- The type I use for PC card memory, they are 3.3 mm thick.
- Type II PC cards are used for expansion devices, and they are 5.0 mm thick.
- Type III PC cards are used for hard drives, and they are 10.5 mm thick.
- Display screens for portable computers are either dual-scan or active matrix.
- Tape carrier packaging processors consume less energy and are used to exclude less heat.
- Good power management is important for long battery life in a portable computer.