1100-Ch01.docx

Follow electrical safety guidelines to prevent electrical fires, injuries, and fatalities. Some printer parts, such as power supplies, contain high voltage. Check the printer manual for the location of high-voltage components. Some components retain a high voltage even after the printer is turned o...

Follow electrical safety guidelines to prevent electrical fires, injuries, and fatalities. Some printer parts, such as power supplies, contain high voltage. Check the printer manual for the location of high-voltage components. Some components retain a high voltage even after the printer is turned off. Electrical devices have certain power requirements. For example, AC adapters are manufactured for specific laptops. Exchanging AC adapters with a different type of laptop or device may cause damage to both the AC adapter and the laptop. Electric equipment must be grounded. If a fault causes metal parts of the equipment to become live with electrical current, the ground will provide a path of least resistance for the current to flow harmlessly away. Typically computer product connect to ground via the power plug. Large equipment such as server racks that house network devices must also be grounded. Electrostatic discharge (ESD) can occur when there is a buildup of an electric charge (static electricity) that exists on a surface which comes into contact with another, differently charged surface. ESD can cause damage to computer equipment if not discharged properly. Follow proper handling guidelines, be aware of environmental issues, and use equipment that stabilizes power to prevent equipment damage and data loss. At least 3,000 volts of static electricity must build up before a person can feel ESD. For example, static electricity can build up on you as you walk across a carpeted floor. When you touch another person, you both receive a shock. If the discharge causes pain or makes a noise, the charge was probably above 10,000 volts. By comparison, less than 30 volts of static electricity can damage a computer component. Static buildup can be discharged by touching a grounded object prior to touching any electronic equipment. This is known as self-grounding ESD can cause permanent damage to electrical components. Follow these recommendations to help prevent ESD damage: - Keep all components in antistatic bags until you are ready to install them. - Use grounded mats on workbenches. - Use grounded floor mats in work areas. - Use antistatic wrist straps when working inside computers. The case of a desktop computer houses the internal components such as the power supply, motherboard, central processing unit (CPU), memory, disk drives, and assorted adapter cards.\ Cases are typically made of plastic, steel, or aluminum and provide the framework to support, protect, and cool the internal components. A device form factor refers to its physical design and look. Desktop computers are available in a variety of form factors including:  - Horizontal case - Full-Size Tower - Compact Tower - All-in-one This list is not exhaustive, as many case manufacturers have their own naming conventions. These may include super tower, full tower, mid tower, mini tower, cube case, and more.\ Computer components tend to generate a lot of heat; therefore, computer cases contain fans that move air through the case. As the air passes warm components, it absorbs heat and then exits the case. This process keeps the computer components from overheating. Cases are also designed to protect against static electricity damage. The computer's internal components are grounded via attachment to the case. **Note**: Computer cases are also referred to as the computer chassis, cabinet, tower, housing, or simply box. Electricity from wall outlets is provided in alternating current (AC). However, all components inside a computer require direct current (DC) power. To obtain DC power, computers use a power supply, as shown here, to convert AC power into a lower voltage DC power. The following describes the various computer desktop power supply form factors that have evolved over time: - **Advanced Technology (AT)** -- This is the original power supply for legacy computer systems now considered obsolete. - **AT Extended (ATX)** -- This is the updated version of the AT but still considered to be obsolete. - **ATX12V** -- This is the most common power supply on the market today. It includes a second motherboard connector to provide dedicated power to the CPU. There are several versions of ATX12V available. - **EPS12V** -- This was originally designed for network servers but is now commonly used in high-end desktop models. - The different connectors also provide different voltages. The most common voltages supplied are 3.3 volts, 5 volts, and 12 volts. The 3.3 volt and 5 volt supplies are typically used by digital circuits, while the 12 volt supply is used to run motors in disk drives and fans. - Power supplies can also be single rail, dual rail, or multi rail. A rail is the printed circuit board (PCB) inside the power supply to which the external cables are connected. A single rail has all of the connectors connected to the same PCB while a multi rail PCB has separate PCBs for each connector. - A computer can tolerate slight fluctuations in power, but a significant deviation can cause the power supply to fail. The motherboard, also known as the system board or the main board, is the backbone of the computer. a motherboard is a printed circuit board (PCB) that contains buses, or electrical pathways, that interconnect electronic components. These components may be soldered directly to the motherboard, or added using sockets, expansion slots, and ports. Central Processing Unit (CPU) - This is considered the brain of the computer. Random Access Memory (RAM) - This is a temporary location to store data and applications Expansion slots - These provide locations to connect additional components. Chipset - This consists of the integrated circuits on the motherboard that control how system hardware interacts with the CPU and motherboard. It also establishes how much memory can be added to a motherboard and the type of connectors on the motherboard. Basic input/output system (BIOS) chip and Unified Extensible Firmware Interface (UEFI) chip - BIOS is used to help boot the computer and manage the flow of data between the hard drive, video card, keyboard, mouse, and more. In modern computers BIOS has been replaced by UEFI. UEFI specifies a different firmware for boot and runtime services. Firmware is programming that allows a computer operating system to control the hardware. SATA, or Serial Advanced Technology Attachment (ATA), is a disk drive interface used for connecting optical drives, hard drives, and solid-state drives to the motherboard. SATA supports hot swapping, which is the ability to replace devices without powering off the computer. Most chipsets consist of the following two types: - **Northbridge** -- Controls high speed access to the RAM and video card. It also controls the speed at which the CPU communicates with all of the other components in the computer. Video capability is sometimes integrated into the Northbridge. - **Southbridge** -- Allows the CPU to communicate with slower speed devices including hard drives, Universal Serial Bus (USB) ports, and expansion slots AT Motherboard Form Factor This is the first type of motherboard included in the list. These products have immense physical dimensions that are ranging up to hundreds of millimeters. Therefore, they require more space for installation and display limited installation abilities inside mobile phones and mini desktop versions. at motherboard form factor Instead, they can be used inside a large computer monitor where sufficient space is available to install the item along with the required drivers and connectors. These units utilize sockets and six-pin plugs for connecting various power sources with each other. Similarly, it requires a great deal of attention to identify the power connectors and might require expert guidance while doing so. Similarly, these materials also require a 12 pin plug to power the motherboard. Hence, they are an ideal choice for large desktops. **ATX (Advanced Technology eXtended)** - **Size**: 305 x 244 mm (12 x 9.6 inches) - **Expansion Slots**: Typically 7 PCIe slots - **RAM Slots**: Usually 4 or more - **Features**: Offers the most expansion options, including multiple GPU setups, extensive cooling solutions, and numerous storage options. - **Use Case**: Ideal for high-end gaming PCs, workstations, and users needing extensive expandability. **Micro-ATX (mATX)** - **Size**: 244 x 244 mm (9.6 x 9.6 inches) - **Expansion Slots**: Typically 4 PCIe slots - **RAM Slots**: Usually 2 to 4 - **Features**: Balances size and expandability, offering a decent number of expansion slots and features in a more compact form. - **Use Case**: Suitable for mid-range gaming PCs and general-purpose builds where space-saving is important but some expandability is still needed. **Mini-ITX** - **Size**: 170 x 170 mm (6.7 x 6.7 inches) - **Expansion Slots**: Typically 1 PCIe slot - **RAM Slots**: Usually 2 - **Features**: Focuses on space efficiency, often used in small form factor (SFF) builds. Limited expansion options but sufficient for compact, portable systems. - **Use Case**: Perfect for small, portable PCs, HTPCs (Home Theater PCs), and minimalist builds. **ITX** - **Size**: Varies, but generally smaller than Mini-ITX - **Expansion Slots**: Varies, often very limited - **RAM Slots**: Varies, often very limited - **Features**: Even more compact than Mini-ITX, used in very specialized or ultra-compact builds. - **Use Case**: Used in niche applications where space is extremely limited, such as embedded systems or very small custom builds. **Key Differences** - **Size**: ATX is the largest, followed by Micro-ATX, Mini-ITX, and then ITX. - **Expansion**: ATX offers the most expansion slots and features, while ITX offers the least. - **Use Case**: ATX is for high-end, expandable systems; Micro-ATX for balanced builds; Mini-ITX for compact systems; and ITX for ultra-compact or specialized builds. The central processing unit (CPU) is responsible for interpreting and executing commands. It handles instructions from the computer\'s other hardware, such as a keyboard, and software. The CPU interprets the instructions and outputs the information to the monitor or performs the requested tasks. The CPU is a small microchip that resides within a CPU package. The CPU package is often referred to as the CPU. CPU packages come in different form factors, each style requiring a particular socket on the motherboard. Common CPU manufacturers include Intel and AMD. The CPU socket is the connection between the motherboard and the processor. Modern CPU sockets and processor packages are built around the following architectures: Pin Grid Array (PGA) - In PGA architecture, the pins are on the underside of the processor package and is inserted into the motherboard CPU socket using zero insertion force (ZIF). - ZIF refers to the amount of force needed to install a CPU into the motherboard socket or slot. Land Grid Array (LGA) - In an LGA architecture, the pins are in the socket instead of on the processor. The flow of current between electronic components generates heat. Computer components perform better when kept cool. If the heat is not removed, the computer may run more slowly. If too much heat builds up, the computer could crash, or components can be damaged. Therefore, it is imperative that computers be kept cool. Computers are kept cool using active and passive cooling solutions. Active solutions require power while passive solutions do not. Passive solutions for cooling usually involve reducing the speed at which a component is operating or adding heat sinks to computer chips. A case fan is considered as active cooling. The figure shows examples of passive and active cooling solutions. Types of Memory A computer might use different types of memory chips. However, all memory chips store data in the form of bytes. A byte is a grouping of digital information and represents information such as letters, numbers, and symbols. Specifically, a byte is a block of eight bits stored as either 0 or 1 in the memory chip. Read-Only Memory - An essential computer chip is the read-only memory (ROM) chip. - ROM chips are located on the motherboard and other circuit boards and contain instructions that can be directly accessed by a CPU. - The instructions stored in ROM include basic operation instructions such as booting the computer and loading the operating system. - ROM is nonvolatile which means that the contents are not erased when the computer is powered off. Random Access Memory - RAM is the temporary working storage for data and programs that are being accessed by the CPU. Unlike ROM, RAM is volatile memory, which means that the contents are erased every time the computer is powered off. - Adding more RAM in a computer enhances the system performance - more RAM increases the memory capacity of the computer to hold and process programs and files - With less RAM, a computer must swap data between RAM and the much slower hard drive. - The maximum amount of RAM that can be installed is limited by the motherboard. Every version of PCIe is backward-compatible with all other versions, for example, if you have a motherboard that supports version 4, you can still use version 3 PCIe components. The speed of the bus will be determined by the lowest version component installed. PCIe can supply up to 25 watts of power to each slot. For a graphics card, it can supply up to 75 watts. For very powerful graphics cards, an additional 75 watts can be supplied by a PCIe power connector from the power supply. A number of different types of devices are available for data storage on a PC, as shown in the figure. Data drives provide non-volatile storage of data, meaning that when the drive loses power, the data is retained and available the next time the drive is powered on. Some drives have fixed media, and other drives have removable media. Some offer the ability to read and write data, while others only allow data to be accessed, but not written. Data storage devices can be classified according to the media on which the data is stored; magnetic like HDD and tape drives, solid state, or optical. **SATA (Serial ATA)** **SATA 1 (SATA I)** - **Data Transfer Rate**: Up to 1.5 Gbps (150 MB/s) - **Introduced**: 2003 - **Use Case**: Basic consumer storage needs **SATA 2 (SATA II)** - **Data Transfer Rate**: Up to 3 Gbps (300 MB/s) - **Introduced**: 2004 - **Improvements**: Enhanced data transfer speed, Native Command Queuing (NCQ) for better performance **SATA 3 (SATA III)** - **Data Transfer Rate**: Up to 6 Gbps (600 MB/s) - **Introduced**: 2009 - [**Improvements**: Further increased data transfer speed, improved efficiency and reliability^1^](https://www.technewstoday.com/sata-2-vs-sata-3/)[^2^](https://driveshero.com/different-types-of-sata-cables/) **SAS (Serial Attached SCSI)** - **Data Transfer Rate**: Up to 12 Gbps for SAS-3, with newer versions supporting even higher speeds - **Use Case**: Enterprise-level storage solutions, high-performance servers - [**Features**: Full-duplex communication, advanced error checking, supports multiple devices per port, higher reliability and performance compared to SATA^3^](https://www.hp.com/us-en/shop/tech-takes/sas-vs-sata)[^4^](https://blog.itcreations.com/sas-vs-sata-choose-wisely/) **Key Differences** - **Performance**: SAS generally offers higher data transfer rates and reliability compared to SATA. - **Use Case**: SATA is more common in consumer-grade PCs, while SAS is used in enterprise environments. - [**Cost**: SAS is typically more expensive due to its advanced features and higher performance](https://www.hp.com/us-en/shop/tech-takes/sas-vs-sata) Solid-state drives (SSD) store data as electrical charges in semiconductor flash memory. This makes SSDs much faster than magnetic HDDs. SSD storage capacity ranges from around 120 GBs to many TBs. SSDs have no moving parts, make no noise, are more energy efficient, and produce less heat than HDDs. Because SSDs have no moving parts to fail, they are considered to be more reliable than HDDs. SSDs come in three form factors: - **Disc drive form factor** -- These are similar to an HDD in which the semiconductor memory is in a closed package that can be mounted in computer cases like an HDD. They can be 2.5, 3.5, and 1.8 inches, although those are rare. - **Expansion cards** -- This plugs directly into the motherboard and mounts in the computer case like other expansion cards. - **mSata or M.2 modules** -- These packages may use a special socket. M.2 is a standard for computer expansion cards. It is a family of standards that specify physical aspects of expansion cards such as connectors and dimension. Optical drives are a type of removable media storage device that use lasers to read and write data on optical media. They were developed to overcome the storage capacity limitations of removable magnetic media such as floppy discs and magnetic storage cartridges. **CD Formats** 1. **CD-ROM (Compact Disc Read-Only Memory)** - **Storage Capacity**: Up to 700 MB - **Description**: Pre-pressed discs used to store data that cannot be modified. 2. **CD-R (Compact Disc Recordable)** - **Storage Capacity**: Up to 700 MB - **Description**: Can be written once and read multiple times. 3. **CD-RW (Compact Disc Rewritable)** - **Storage Capacity**: Up to 700 MB - **Description**: Can be written, erased, and rewritten multiple times. **DVD Formats** 4. **DVD-ROM (Digital Versatile Disc Read-Only Memory)** - **Storage Capacity**: 4.7 GB (single-layer), 8.5 GB (dual-layer) - **Description**: Pre-pressed discs used to store data that cannot be modified. 5. **DVD-RAM (Digital Versatile Disc Random Access Memory)** - **Storage Capacity**: 4.7 GB (single-sided), 9.4 GB (double-sided) - **Description**: Can be written, erased, and rewritten multiple times with random access capability. **Blu-ray Disc Formats** 6. **BD-ROM (Blu-ray Disc Read-Only Memory)** - **Storage Capacity**: 25 GB (single-layer), 50 GB (dual-layer) - **Description**: Pre-pressed discs used to store data that cannot be modified. 7. **BD-R (Blu-ray Disc Recordable)** - **Storage Capacity**: 25 GB (single-layer), 50 GB (dual-layer) - **Description**: Can be written once and read multiple times. 8. **BD-RE (Blu-ray Disc Rewritable)** - **Storage Capacity**: 25 GB (single-layer), 50 GB (dual-layer) - **Description**: Can be written, erased, and rewritten multiple times. **Video Ports and Cables** A video port connects a monitor cable to a computer. Video ports and monitor cables transfer analog signals, digital signals, or both. Computers are digital devices that create digital signals. The digital signals are sent to the graphics card where they are transmitted through a cable to a display. There are 5 types of DVI that are available for digital and analog output and also for single link and dual link which offers extra bandwidth. DVI-D only supports digital devices and outputs. DVI-A will only support analog output. DVI-I supports digital outputs and analog devices.  There are currently two main types of DVI connectors, DVI-I and DVI-D.DVI-D provides a digital only signal, while DVI-I can support digital and analog signals. DVI is disappearing as quickly as it appeared. It\'s still seen in some monitors alongside VGA, which is finally starting to fade in favor of HDMI. **Adapters and Converters** There are many connection standards in use today. Many are interoperable but require specialized components. These components are called adapters and converters: - **Adapter** -- This is a component that physically connects one technology to another. For example, a DVI to HDMI adapter. The adapter could be one component or a cable with different ends. - **Converter** -- This performs the same function as an adapter but also translates the signals from one technology to the other. For example, a USB 3.0 to SATA converter enables a hard disk drive to be used as a flash drive. An output device takes binary information (ones and zeroes) from the computer and converts it into a form that is easily understood by the user. Monitors and projectors are output devices that create visual and audio signals for the user. Virtual Reality (VR) headsets are another type of output device. Televisions may also be output devices. Printers are visual output devices that create hard copies of computer files. **Monitor** Most monitors use one of three types of technology: LCD, LED, or OLED.\ Liquid crystal display (LCD) has two polarizing filters with a liquid crystal solution between them. An electronic current aligns the crystals so that light can pass through or not pass through, creating the image.\ Light-emitting diode (LED) is an LCD display that uses LED backlighting. LED has lower power consumption than standard LCD backlighting. The panel is thinner, lighter, brighter, and has better contrast than LCD.\ Organic LED (OLED) is a type of LED display that uses a layer of organic material which responds to electrical stimulus to emit light. Each pixel lights individually, resulting in much deeper black levels than LED. Virtual Reality (VR) uses computer technology to create a simulated, three-dimensional environment. The user feels immersed in this 'virtual world' and manipulates it. A VR headset completely encases the upper portion of users' faces, not allowing in any ambient light from their surroundings. Most VR experiences have three-dimensional images that seem life-sized to the user. VR experiences also track a user\'s motions, and adjust the images on the user\'s display accordingly. Augmented Reality (AR) uses similar technology but superimposes images and audio over the real world in real time. AR can provide users with immediate access to information about their real surroundings. An AR headset usually does not close off ambient light to users, allowing them to see their real life surroundings. Not all AR requires a headset. Some AR can simply be downloaded onto a smart phone. Pokemon GO is an early version of an AR game that uses a player's smart phone to 'see and capture' virtual objects in the real world. Other AR devices are smart glasses. They weigh much less than the headsets and are often designed for a specific audience, such as cyclists. Printers are output devices that create hard copies of files. A hard copy might be a on a sheet of paper. It could also be a plastic form created from a 3D printer. Today's printers may be wired, wireless, or both. They use different technology to create the image you see. All printers require printing material (such as ink, toner, liquid plastic, etc.) and a method to place it accurately on the paper or extrude it into the desired shape. All printers have hardware that must be maintained. Most printers also have software, in the form of drivers that must be kept up to date.