A comp. contain many electric , electronic , and mechanical components known as hardware. These components includes input and output devices, a system unit , storage devices, and communication devices common computer hardware components.
- 1 Computer hardware
- 2 Computer Hardware Full Explain
- 3 Use of Computers in life and Control Systems
- 4 Control System / Moore’s Flashlight Demo
- 5 Computer Hardware – CPU, RAM, and persistent storage
- 6 1. CPU
- 7 Aside: CPU “Cores”
- 8 CPU Examples
- 9 CPU Variant: GPU – Graphics Processing Unit
- 10 2. RAM
- 11 RAM Examples
- 12 3. Persistent Storage: Hard Drive, Flash Drive
- 13 Persistent Storage, Newer Technology: Flash
- 14 File System
- 15 Persistent Storage Examples
- 16 Pictures of Hardware
- 17 Microcontroller – Cheap Computer Chip
- 18 Arduino Computer
A Computer keyboard contain keys you press to enter data into the computer. For security purpose some keyboard include a fingerprint reader, which allow to work with the computer only if your fingerprint is recognized.
A Mouse is a small handheld device. With the mouse, you control the movement of pointer, and you make selections from the screen.
A Microphone allow you to speak into the computer. You can use microphone for multipurpose like record the own and other person voices.
A Scanner converts printed material (such as text and pictures) into the form the computer can use.
A Webcam is a digital video camera that allow you to create movies or take pictures and store them on the computer instead of on tape or film.
A Digital pen allow to work same as a mouse but in this situation mouse replace with Digital pen to make easily digital art.
An Output Devices is any hardware components that conveys information to one or more people. Three commonly used output devices are a printer, a monitor , and speakers.
A Printer produces text and graphical on a physical medium such as a paper. A monitor displays text, graphics, and videos on a screen. Speakers allow to hear music, voices, and other audio (sound).
The System Unit is a case that contains the electronic components of the comp. that are used to process data. The circuitry of the system unit usually is part of or is connected to a circuit board called the motherboard.
Two main components on the motherboard are the processor and memory. The processor also called a CPU (Central Processing Unit), is the electronic components that interprets and carries out the basic instructions that operate carries out the basic instruction operate the computer. Memory consists of electronic components, that store instruction waiting to be executed the data needed by those instruction. Although some forms of memory are permanents, most memory keeps data and instruction temporary, which means its contents are erased when the computer is shutdown.
This Storage holds data, instructions, and information for future use, For Example, Computer can store hundreds or millions of customer name, addresses and phone numbers. Storage holds these items permanently.
A computer keeps data, instruction, and information on storage media. Examples of Storage media are USB (Universal Serial Bus), hard disk, optical disk, and memory card. A storage device records and retries items to and from storage media. Drives and readers/writers, which are a type of storage devices. For Example, a DVD drive (storage device) accept a DVD (storage media). Storage devices often function as a source of input because the transfer of items from storage to memory.
A hard drive provides much greater storage capacity than a USB flash drive. The average hard disk can hold more than 320 billion characters. Hard disks are enclosed in an airtight, sealed case. Although some are portable, most are housed inside the system unit . Portable hard disks are either external or removable. An external hard disk is a separate free-standing unit, whereas you insert and remove a removable hard disk from the computer or a device connected to the computer.
An optical disc is a flat, round, portable metal disk with plastic coating. CD’s, DVDs, and blue-ray Discs are thee types of optical discs. A CD can hold from 650 million to 1 billion character. Some DVDs can store two-full length movie and hundreds of video songs. Blue-ray Discs can store about 46 hours of standard videos or billion characters.
Some mobile devices, such as digital cameras, use memory cards as the storage media. You can use a card reader/writer to transfer the stored items, such as digital photos, from the memory card to a computer or printer. In this time hundreds of mobile phone Companies provide a huge amount of memory storage, built on Mobile Phone.
A communication Devices is hardware components that enable a computer to send data, and receive data, instruction, and information to and from one or more computers or mobile devices. A widely used communication device is a modem and routers.
Computer Hardware Full Explain
- Computers have two main parts: hardware and software
- Like piano (hardware) and music (software)
- In this section: hardware
The computer is an amazingly useful general-purpose technology, to the point that now cameras, phones, thermostats, and more are all now little computers. This section will introduce major parts and themes of how computer hardware works. “Hardware” refers the physical parts of the computer, and “software” refers to the code that runs on the computer.
Use of Computers in life and Control Systems
- Control system: responds to external state
- e.g. car engine: vary fuel mix based on temperature
- e.g. set off the airbag on high G-forces from collision
- Chips are a great, cheap way to build control systems
- The pre-computer control systems did not work so well
- One reason cars work so much better today
Control System / Moore’s Flashlight Demo
- Maglite XL200 flashlight has a chip in it
- Example of a control system
- Moore’s law makes this application of a chip feasible
- Flashlight converts angular position to brightness. (1-click)
- Also has an angle to blink-speed mode. (2-clicks)
Computer Hardware – CPU, RAM, and persistent storage
Now let’s talk about the three major parts that make up a computer — CPU, RAM, and Persistent Storage. These three are found in all computers: laptops, smartphones, and tablets.
- CPU – Central Processing Unit
- Acts like a brain: follows the instructions in the code
- “general” – images, networking, math .. all on the CPU
- Performs computations, e.g. add two numbers
- vs. RAM and persistent storage which just store data
- “gigahertz” = 1 billion operations per second
- A “2 gigahertz” CPU performs 2 billion operations per second
Aside: CPU “Cores”
- Modern CPU chips have multiple “cores”
- Each core is a semi-independent CPU
- Key: having 4 cores is not 4x faster than having 1 core
- i.e. 4 cars does not get you there faster than 1 car
- Diminishing returns
- More than 4 cores is often useless
- e.g. Run button – “print information,” do some math
- e.g. Send text message – format the bytes, send out the bytes, verify they were sent
CPU Variant: GPU – Graphics Processing Unit
- Like the CPU, but specialized to handle images
- Computer games use the GPU heavily
- Modern CPUs are mostly fast enough, more energy going into GPUs
- RAM – Random Access Memory
- Acts like a whiteboard
- Temporary, working storage bytes
- RAM stores both code and data (temporarily)
- e.g. open an image in Photoshop
– image data loaded into the bytes of RAM
- e.g. adding 2 to a number in a calculator
– manipulating bytes in RAM
-RAM is not persistent. State is gone when power turned off
-e.g. You’re working on a doc, then power goes out and you lose your work (vs. “Save”)
RAM – Random Access Memory, or just “memory”. RAM is the working scratchpad memory the computer uses to store code and data that are being actively used. RAM is effectively a storage area of bytes under the control of the CPU. RAM is relatively fast and able to retrieve the value of any particular byte in a few nanoseconds (1 nanosecond is 1 billionth of a second). The other main feature of RAM is that it only keeps its state so long as it is supplied with power — RAM is not “persistent” storage.
Suppose you are working on your computer and it suddenly loses power and the screen goes blank. You understand that what you were working on is gone. RAM has been wiped clean, leaving you only with what you last saved to disk (below).
- You have many tabs open in your browser
– the data for each tab is in RAM
- A program is running
– the code of the program is in RAM
- A program is manipulating a large image
– the data of the image is in RAM
- e.g. you can run out of RAM – cannot open a new tab or program because all the RAM is in use
- Aside: now phones have 2-4GB of RAM … enough for most purposes
3. Persistent Storage: Hard Drive, Flash Drive
- Persistent storage of bytes
- “Persistent” means preserved even when not powered
- e.g. Hard drive – stores bytes as a magnetic pattern on a spinning disk
– aka “hard disk”
– High pitch spinning sound you may have heard
- Hard drives have been the main, persistent storage tech for a long time
- BUT now flash is getting more popular.
How a Hard Drive Works Video (Webm is an open standard video format, works in Firefox and Chrome). 4:30 in the video to see some reading/writing of bits.
Persistent Storage, Newer Technology: Flash
- “Flash” is a transistor-like persistent storage technology
“solid state” – no moving parts
-aka “Flash drive”
-aka “Flash memory”
-aka “SSD”: Solid State Disk
- Flash is better than a hard drive in every way but cost – faster, more reliable, less power
- Flash is more expensive per byte
- Formats: usb key, SD card in camera, flash storage built into a phone or tablet or computer
- Flash used to be very expensive, so most computers used hard disks
- Flash is getting cheaper (Moore’s law)
- However per-byte, hard drives are still substantially cheaper
- Not to be confused with “Adobe Flash”, a proprietary media format
- Warning: flash does not persist forever. It may not hold the bits past 10 or 20 years. Nobody knows for sure
Persistent storage – long term storage for bytes as files and folders. Persistent means that the bytes are stored, even when power is removed. A laptop might use a spinning hard drive (also known as “hard disk”) for persistent storage of files. Or it could use a “flash drive”, also known as a Solid State Disk (SSD), to store bytes on flash chips. The hard drive reads and writes magnetic patterns on a spinning metal disk to store the bytes, while flash is “solid state”: no moving parts, just silicon chips with tiny groups of electrons to store the bytes. In either case, the storage is persistent, in that it maintains its state even when the power is off.
A flash drive is faster and uses less power than a hard disk. However, per byte, flash is significantly more expensive than hard drive storage. Flash has been getting cheaper, so it may take over niches at the expense of hard drives. Flash is much slower than RAM, so it is not a good replacement for RAM. Note that Adobe Flash is an unrelated concept; it is a proprietary media format.
Flash storage is what underlies USB thumb drives, SD cards for use in cameras, or the built-in storage in a tablet or phone.
- How are the bytes in persistent storage organized?
- e.g. Bytes on a flash drive?
- “File system” – organize the bytes of persistent storage, files and folders
- “File” – a name, a handle to a block of bytes
- e.g. “flowers.jpg” refers to 48KB of image data bytes
The hard drive or flash drive provides persistent storage as a flat area of bytes without much structure. Typically the hard disk or flash disk is formatted with a “file system” which organizes the bytes into the familiar pattern of files and directories, where each file and directory has a somewhat useful name like “resume.txt”. When you connect the drive to a computer, the computer presents the drive’s file system to the user, allowing them open files, move file around, etc.
Essentially, each file in the file system refers to a block of bytes, so the “flowers.jpg” name refers to a block of 48KB of bytes which are the data of that image. The file system in effect gives the user a name (and probably an icon) for a block of data bytes, and allows the user to perform operations on that data, like move it or copy it or open it with a program. The file system also tracks information about the bytes: how many there are, the time they were last modified.
Microsoft uses the proprietary NTFS file system, and Mac OS X has its Apple proprietary HFS+ equivalent. Many devices (cameras, MP3 players) use the very old Microsoft FAT32 file system on their flash cards. FAT32 is an old and primitive file system, but it is good where wide support is important.
Persistent Storage Examples
- This one is easy to understand, since you have used files and files sytems
- e.g. 100 separate 1 GB video files .. need 100 GB of storage capacity
Pictures of Hardware
Below are images of a low-end Shuttle computer with a 1.8ghz CPU, 512MB of RAM, and a 160GB hard drive. It cost about $200 in around 2008. It broke, and so became a classroom example.
Here is the flat “motherboard”, a little smaller than a 8.5 x 11 piece of paper, that the various components plug in to. At the center is the CPU. At the far right is the RAM memory. Just to the right of the CPU are a couple support chips. Prominently, one of the chips is covered with a copper “heatsink” .. this presses tightly against the chip, dissipating the heat from the chip into the surrounding air. The CPU also had a very large heatsink, but it was removed to make the CPU visible.
- CPU metal package, held by lever
- Copper heatsink
The CPU is held tightly against the motherboard by a little lever mechanism. Here the mechanism is released so the CPU can be picked up. The fingernail sized CPU is packaged underneath this metal cover which helps conduct the heat from the CPU up to its heatsink. The gray stuff on the metal chip cover is “thermal paste”, a material which helps conduct heat from the chip housing to its (not shown) heatsink.
- CPU chip in metal package
- Heatsink has been removed
- Bottom of package .. many connections (little wires)
Flipping the CPU over shows the little gold pads on the bottom of the CPU. Each pad is connected by a very fine wire to a spot on the silicon chip.
Here is a picture of another chip, but with the top packaging removed. You see the pinky-fingernail silicon chip at the center with the tiny transistor details etched onto it. At the chip edge, see the very fine wires connecting parts of the chip to outside pads (CC licensed attribution sharealke 3. wikipedia user Zephyris)
Now looking from the side, the heatsink and the RAM memory card can be seen more clearly, sticking up from the motherboard.
- RAM memory card
- Plugs in to motherboard
- 512 MB card (4 chips)
RAM is built with a few chips packaged together onto a little card known as a DIMM that plugs into the motherboard (dual inline memory module). Here we see the RAM DIMM removed from its motherboard socket. This is a 512MB DIMM built with 4 chips. A few years earlier, this DIMM might have required 8 chips in order to store 512MB .. Moore’s law in action.
This is a hard drive that connects to the motherboard with the visible standard SATA connector. This is a 160GB, “3.5 inch” drive referring to the diameter of the spinning disk inside; the whole drive is about the size of small paperback book. This is a standard disk size to use inside a desktop computer. Laptop computers use 2.5 inch drives, which are a bit smaller.
- 160 GB hard drive (persistent storage)
- i.e. persistent
- Connects to motherboard with standard SATA cable
This is a USB flash drive that, like a hard drive, provides persistent byte storage. This is also known as a “thumb drive” or “USB key”. It is essentially a USB jack connected to a flash storage chip with some support electronics:
- Flash drive (the other type of persistent storage)
- i.e. persistent
- Contains a flash chip, solid state
- SD Card, similar idea
Here it is taken apart, showing the flash chip that actually stores the bytes. This chip can store about 1 billion bits .. how many bytes is that? (A: 8 bits per byte, so that’s about 125 MB)
Here is a “SD Card” which provides storage in a camera. It’s very similar to the USB flash drive, just a different shape.
Microcontroller – Cheap Computer Chip
- Complete computer on one chip
- Small CPU, RAM, storage (Moore’s law)
- Chip can cost under $1
- Car, microwave, thermostat
- This is an “arduino” board, microcontroller chip (CPU, RAM, storage all in one)
- As low as $10
- Open source, free, not Windows only, tinkering
- Art project — switches, sensors, lights