CompTIA A+ Cheat Sheet

CompTIA A+ Cheat Sheet There are two sections to this guide: The first part involves facts for the first test (220-1001) and the second part goes over information for the second test (220-1002). 220-1001 Materials Motherboard = connect all the components. Form factors may include ATX, microATX, and ITX. Types of expansion buses include PCI Express (PCIe) and PCI. Intel chipsets attach to CPU via DMI or QPI. AMD CPU-to-chipset connection is HyperTransport. BIOS/UEFI finds, tests, and initializes components and boots to the hard drive, optical disc, USB flash drive, or network by PXE. CMOS stores time/date and passwords. CMOS is powered by a CR2032 lithium battery. BIOS/UEFI configurations include: time/date, boot device order, passwords, power management, WOL, monitoring, clock and bus speeds, virtualization support (Intel VT or AMD-V), enable/disable devices, diagnostics, security, and intrusion detection. The central processing unit (CPU) or processor handles most calculations. Intel CPUs use the following sockets: LGA775, 1150, 1155, 1156, 1366, and 2011. AMD CPUs use AM3, AM3+, FM1, FM2, and FM2+ sockets. L1/L2 cache in each core. L3 cache is shared with the entire CPU. A thermal compound (paste) is used whenever the heat sink is installed. Heat sinks are either active with a fan or passive, without the use of a fan. Liquid-based cooling systems can reduce heat in an effective manner. Random Access Memory (RAM) DIMMs comprise of DDR (184 pins), DDR2 (240 pins), DDR3 (240 pins) and DDR4 (288 pins). RAM SODIMMs include DDR (200 pin), DDR2 (200 pin), DDR3 (204 pin) and DDR4 (260 pin). An example of a DDR3-1600 data transfer calculation is the follows: 1600 MT/s ×8 = 12,800 MB/s. Dual-channel is double width, 128-bit bus. Triple-channel is 3x the width, 192-bit bus. Quad-channel is 4x the width, 256-bit bus. Latency measured as CL or CAS. A “dual-rail” PSU separate and limits the current in each wire to avoid overheating. Hard drives store data. Their types include: HDD: Hard disk drive SSD: Solid-state drive (flash-based) SATA: A serial ATA utilizes a 15-pin power connector and 7-pin data connector. Rev 1 (1.5 Gb/s), Rev 2 (3 Gb/s), Rev 3 (6 Gb/s), Rev 3.2 (SATA Express) (16 Gb/s). Redundant Array of Independent Disk (RAID). RAID 0 = striping, RAID 1 = mirroring, and RAID 5 = striping with parity. RAID 10 = mirrored sets in a striped set. RAID 0 = not fault-tolerant. RAID 1 using two disk controllers = disk duplexing. Optical disc drives use changeable media to store as well as retrieve data. Various optical discs include: CD-ROM: Data CDs commonly hold 700 MB and can read and write at up to 52x (7.8 MB/s). They can also rewrite at up to 32x (4.8 MB/s). DVD-ROM: DVDs have a capacity that ranges from 4.7 GB (DVD-5) to 17 GB (DVD-18 dual-sided and dual-layered). Recording technologies: DVD+R, DVD-R, DVD+RW, and DVD-RW. Blu-ray: Blu-ray discs (BDs) are used for games and HD. They have a capacity of 25 to 128 GB (mini-discs 7.8 or 15.6 GB) with a write speed of 1x to 16x (36 Mb/s to 576 Mb/s). Solid-state media comprises of solid-state hard drives (SSDs), USB flash drives, CompactFlash and Secure Digital (SD) cards. Laptops are miniature versions of desktop PCs that are easily transportable. They have items that can be replaced, such as keyboards, touchpads, SODIMM RAM, displays, inverters, batteries, optical disc drives, smart card readers and hard drives (SSD, HDD, or hybrid). Laptops use M.2, Mini PCIe, and Mini PCI (internal) and ExpressCard /34 and /54 (external) technologies. Video cards connect to motherboards by way of x16 PCIe or PCI expansion slots. Video connector types and cables include DVI, VGA, HDMI, Mini-HDMI, DisplayPort, Mini DisplayPort, S-Video, Component Video/RGB, and Composite. Typical color depths may involve 16bit, 24-bit and 32-bit. Resolutions are typically 1280×720 (720p 16:9, aspect ratio), 1920×1080 (HD 1080p, 16:9 aspect ratio), 1366×786 (16:9), 1680×1050 (WSXGA+, 8:5 aspect ratio), 1920×1200 (WUXGA, 8:5), and 640×480 (VGA, 4:3). TN = twisted nematic; IPS = in-plane switching; IPS holds a wider viewing angle. Sound cards link as x1 PCIe (or PCI cards) and will typically have PC 99 color-coded 1/8" mini-jacks for I/O and speakers and optical I/Os known as S/PDIF. USB (Universal Serial Bus) could hold up to 127 devices. USB 1.1 (full speed) runs at 12 Mb/s by a max cable length of 3 meters. USB 2.0 (highspeed) runs at 480 Mb/s by a max cable length of 5 meters. USB 3.0 (SuperSpeed) runs at 5 Gb/s. USB 3.1 (SuperSpeed+) runs at 10 Gb/s. Version 3.x ports are blue. Type A/Type B connectors are utilized by desktops/laptops, and mini- and micro-connectors = used by tablets/smartphones. Type C: one-third size of a Type A plug. Type C also pairs great with USB 3.1 standard. IEEE 1394a or FireWire runs at 400 Mb/s. IEEE 1394b runs at 800 Mb/s. IEEE 1394 chains could hold a max of 63 devices. Thunderbolt: Ver 1 is equivalent to 10 Gb/s and utilizes DisplayPort; Ver 2 is equivalent to 20 Gb/s (also DisplayPort); Ver 3 is equivalent to 40 Gb/s and utilizes USB Type C. The image processing of laser printing involves Processing, Charging, Exposing, Developing, Transferring, Fusing and Cleaning. Printer configuration settings: duplexing is simply printing on both sides; collating involves printing several jobs in a sequence; orientation is either portrait or landscape; quality is the DPI (600 or 1200). Custom PCs include audio/video workstations. They require special A/V cards, fast hard drives, multiple monitors; CAD/CAM workstations will require powerful multicore CPUs, high-end video cards, maximized RAM; home server PCs (gigabit NIC, RAID arrays, print sharing, file sharing, media streaming); HTPCs (compact form factor, surround sound, HDMI output, TV tuner); gaming PCs (multicore CPU, high-end video, high-def sound, high-end cooling); thin clients (low resources, meets minimum requirements for OS, relies on server, diskless, embedded OS, network connectivity); virtualization workstations (strong CPU and plenty of RAM). Type 1 hypervisor is bare or native metal. Type 2 is hosted and runs on top of OS. LAN = local area network. WAN = wide area network. MAN = metropolitan area network. PAN = personal area network. Switches connect computers in a LAN. Routers connect two or more LANs to the Internet. Firewalls protect computers as well as networks from unwanted meddling. IDS = intrusion detection system. IPS = intrusion prevention system. UTM = unified threat management. Networking connectors: twisted pair (RJ45, RJ11); fiber optic (SC, ST, and LC); coaxial (F-connector, BNC). 568B standard: 1. White/orange, 2. Orange, 3. White/green, 4. Blue, 5. White/ blue, 6. Green, 7. White/brown, 8. Brown. IPv4 addresses are 32-bit dotted-decimal numbers, such as 192.168.1.1. They can be manually inputted or dynamically assigned (DHCP). IP classes include: Class A range: 1–126, subnet mask: 255.0.0.0. Private: 10.x.x.x Class B range: 128–191, subnet mask: 255.255.0.0. Private: 172.16.0.0– 172.31.255.255 Class C range: 192–223, subnet mask: 255.255.255.0. Private: 192.168.x.x Loopback is 127.0.0.1 APIPA is 169.254.x.x (also known as link-local) CIDR: Classless Inter-Domain Rout- ing addresses use a prefix (example: 10.150.23.58/24). The /24 indicates a subnet mask of 255.255.255.0 IPv6 addresses are 128-bit hexadecimal numbers, such as 2001:7120:0000:8001: 0000:0000:0000:1F10. ::1 is the loopback address. Unicast IPv6 addresses are the most common type and are assigned to a single interface. Common network speeds are 1000 Mb/s (gigabit Ethernet) and 10 Gb/s (10 Gb Ethernet). Networking protocols involve… FTP (File Transfer Protocol). Port 21 SSH (Secure Shell). Port 22 Port 23 SMTP (Simple Mail Transfer Protocol). Port 25 (can use port 587) DNS (Domain Naming System). Port 53 HTTP (Hypertext Transfer Protocol). Port 80 POP3 (Post Office Protocol). Port 110 IMAP (Internet Message Access Protocol). Port 143 HTTPS (HTTP Secure). Port 443 SMB (Server Message Block). Port 445, 137–139 AFP (Apple Filing Protocol). Port 548 (or 427) RDP (Remote Desktop Protocol). Port 3389 Cabling standards contain… Category 3: Rated for 10 Mb/s Category 5: Rated for 100 Mb/s Category 5e: Rated for 100 Mb/s and gigabit networks Category 6/6a: Rated for gigabit and 10 Gb/s networks Category 7: Rated for gigabit and 10 Gb/s networks Plenum-rated cable: Fire-resistant cable created for the following: airways, conduits and areas sprinklers cannot reach. Wireless Ethernet versions, including name, data transfer rate, frequency and modulation used: 802.11a, 54 Mb/s, 5 GHz 802.11b, 11 Mb/s, 2.4 GHz 802.11g, 54 Mb/s, 2.4 GHz 802.11n, 300/600 Mb/s, 5 and 2.4 GHz 802.11ac, 1.7 Gb/s and beyond, 5 GHz Bluetooth is a short-range technology designed to simplify communication and connectivity among network devices. Bluetooth is grouped into three classes: Class I has a maximum transmission range of 100 meters; Class II (the most popular) has a range of 10 meters; Class III is short range and hardly used at 1 meter. Bluetooth Version 1’s maximum data transfer rate of 721 Kb/s; Version 2 = 2.1 Mb/s, Version 3 = 24 Mb/s. NAT (Network Address Translation): the process of modifying an IP address as it crosses a router. It translates from one network to another. Port forwarding forwards an outside network port to an internal IP address and port. 220-1002 Materials CompTIA 6-step Troubleshooting Theory 1. Identify the problem. 2. Establish a theory of probable cause. (Question the obvious.) 3. Test the theory to determine cause. 4. Create an action plan to solve the problem and apply the solution. 5. Verify the full system work and, if applicable, create measures to prevent future issues. 6. Document findings, actions, and outcomes. Windows 8.1 min. requirements: CPU = 1 GHz; RAM = 1 GB for 32-bit, 2 GB for 64-bit; free disk space = 16 GB for 32- bit, 20 GB for 64-bit. Windows 7 min. requirements: CPU = 1 GHz; RAM = 1 GB for 32-bit, 2 GB for 64-bit; free disk space = 16 GB for 32- bit, 20 GB for 64-bit. Windows Vista min. requirements: CPU = 800 MHz; RAM = 512 MB; free disk space =15 GB. Command Prompt is a Windows command-line utility. To run in elevated mode: (Windows 8) Right-click start button and select Command Prompt; (Windows 7/Vista) Click Start > All Programs > Accessories, right-click Command Prompt, then select Run as administrator. All versions: Type CMD in search field, then select by pressing Ctrl+Shift+Enter. Snap-ins are basic console windows that add to a Microsoft Management Console (MMC). An example would be Computer Management and Performance Monitor. Libraries in Windows 8 and 7 logically represent user-defined collections of folders (Documents, Music, Pictures, Videos). Common system tools involve Device Manager, System Information tool, Task Manager, and Msconfig. User data can be migrated using Windows Easy Transfer and the User State Migration Tool (USMT). The Registry: a database storing all settings for Windows. You can access it by opening the Run prompt and typing regedit.exe. Hives store settings; a commonly modified hive is HKEY_LOCAL_MACHINE. Remote Desktop software helps you see and control the GUI of a remote computer. The %windir% (or %systemroot%) in Windows 8/7/Vista is C:\Windows by default. Windows 8/7/Vista boot files include Bootmgr, Winload.exe, BCD. Bootrec /fixboot repairs Bootmgr, Bootrec /fixmbr rewrites the master boot record, and Bootrec /rebuildbcd rebuilds the boot configuration data store. In Windows, DIR is the directory command. Directories are added with the MD command, removed with RD command and navigated with the CD command. Files can be manipulated with del (deletes), copy (copies files), xcopy (copies multiple files and directory trees), robocopy (robust file copy, replaces xcopy). Drives can be manipulated with format (writes new file system) or diskpart (does everything Disk Management does but in the Command Prompt). File checking command-line tools are used in Windows and can include Chkdsk (/F fixes errors; /R locates bad areas and recovers information) and SFC (System File Checker). SFC /scannow is common. A hard drive using MBR (master boot record) can have four partitions: a max of four partitions but only a single extended partition. Logical drives are segments of an extended partition. The Active partition is what’s booted from, and it usually contains the OS. A volume is any section of a drive with a letter. A hard drive using GPT (GUID Partition Table) can have 128 partitions and go farther than the MBR’s 2 TB limit. The GPT is stored in multiple locations. Requires UEFI- compliant motherboard. File systems include NTFS (main file system in Windows), FAT32 (older system), CDFS (Compact Disc File System), exFAT (Extended FAT, adjusted for flash drives), NFS (Network File System, Linux systems), ext3 and ext4 (extended file systems, popular in Linux). A service pack (SP) is a collection of updates, bug fixes, updated drivers and security fixes installed from one downloadable package or one disc. Windows 8 and 8.1 do not use service packs. Windows Update can be accessed from the Control Panel and Start > All Programs > Windows Update (Windows 7/Vista). Backups can be created in Windows 8 with File History, in Windows 7 with Backup and Restore, and in Vista with Backup Status and Configuration. System Restore can fix issues produced by defective hardware or software by going back to an earlier time. F8 brings up the Advanced Boot Options Menu (ABOM) that includes options such as Safe Mode, Enable low-resolution video, and Last Known Good Configuration. Safe Mode can boot the system with minimal drivers, which must be enabled in Windows 8. if possible. The Windows Recovery Environment (Windows RE) contains system recovery options such as Startup Repair, System Restore and Command Prompt. The Event Viewer cautions about potential problems and shows errors as they occur within three main log files: System, Application and Security. Security displays auditing information. A stop error (or a Blue Screen of Death or BSOD) halts the operating system and shows a blue screen with some text and code. The stop error could be caused by faulty hardware or bad drivers. Processes can be stopped in Task Manager or with the taskkill command in the Command Prompt. Tasklist shows a list of processes currently running. Wireless encryption protocols include WEP (Wired Equivalent Privacy), 64-bit key size, deprecated WPA (Wi-Fi Protected Access), version 2 is 256-bit TKIP (Temporal Key Integrity Protocol), 128-bit, deprecated AES (Advanced Encryption Standard), 128-bit, 192-bit, and 256-bit Best combination is WPA2 with AES (as of writing of this book.) Cloud types: SaaS (software as a service), IaaS (infrastructure as a service), PaaS (platform as a service). Malicious software: This is known as malware, which includes: Virus: A virus is a code that runs on a computer without your knowledge. It infects the computer when the code is executed. Some types include Boot Sector, Macro, Program, Polymorphic, Stealth, and Multipartite. Worms: Similar to viruses but they self-replicate. Trojan Horses: They appear to perform helpful functions but are actually executing malicious functions in the background. Spyware: Malicious software that’s either downloaded unknowingly from a website or installed with some other third-party software. Rootkit: Software created to attain administrator-level access to the system core without being detected. Ransomware: Software designed to hold the computer hostage until the user pays.