USB

USB 2.0 - Hi-Speed USB - FAQ


What is USB 2.0?
USB 2.0 is a complete overhaul to the Universal Serial Bus input/output bus protocol which allows much higher speeds than the older USB 1.1 standard did.

USB 1.1 allowed a maximum transfer rate of 12Mbits/second. That rate is now called 'USB.' Though some manufacturers label their products Full-Speed USB. Note that this seems a bit deceptive. Its easy to mistake Full-Speed for Hi-Speed.

As an aside, USB mice and keyboards need only 1.5Mbits/s to function. That performance level is also named 'USB' by the USB Promoter Group.

To sum it up, USB 2.0 specification incorporates three speeds: Hi-Speed, Full-Speed and Low-Speed. You as a consumer don't need to figure out all the jargons. Just keep in mind that only 'Hi-Speed USB' and 'USB' host and devices exist.

How do I know if my PC has USB 2.0?
You can identify whether your PC has Hi-Speed or not relatively easy. Open Device Manager and expand the Universal Serial Bus section. There should be an "Enhanced" USB host controller present.

Windows 98 systems may use a different name, because Hi-Speed USB drivers in these operating systems are not provided directly from Microsoft (Windows ME, 2000 and XP get their drivers through Windows Update).

These drivers are provided by the manufacturer, and may carry the maker's name (i.e. ADS, Belkin, IOGear, Siig, etc.). There should also be two standard version USB host controllers present as well. They are embedded in the USB chip which routes the differing USB speeds accordingly without user intervention.

There are currently 6 manufacturers of the Hi-Speed USB host silicon themselves:

• ALi (Acer Labs)
  

• Intel
  

• NEC
  

• SiS
  

• VIA
  

• nVidia (shows as "Standard" controller
  

Any other brand name that appears in Device Manager would likely be an add-in Hi-Speed USB PCI card. The makers above do not make add-in cards, but they do make the chips that are used in them.

How do troubleshoot "unknown device" error listed in Device Manager?

• The USB device or the USB adapter requires its own power source. If your USB device or adapter came with an AC power "brick", try connecting it.
  

• Here's a likely one - the front USB ports on your PC case may be misconnected. I've seen them that way from the factory. It's a good idea to check the connections against specifications. The standard order of connection is Red, White, Green, and Black. No more than 4 wires per USB bank are needed.
  

• Defective device. Do not assume that all PC components work correctly out of the box. I've seen many new USB devices that do not work. If you can, try the device on another PC.
  

• All drivers are not installed. Some devices will require installing the driver package before plugging in the device. Some devices will also require basic USB files from the Windows CD before the unit will function. The general rule is to always follow installation directions precisely and to have the Windows CD ready.
  

How fast is USB 2.0?
USB 2.0 has a raw data rate at 480Mbps, and it is rated 40 times faster than its predecessor interface, USB 1.1, which tops at 12Mbps. Originally, USB 2.0 was intended to go only as fast as 240Mbps.

How will consumers benefit from USB 2.0?
With speed 40 times more than that of USB 1.1, USB 2.0 broaden the range of external peripherals that can be used on a computer. Even with multiple high-speed peripherals connected to a USB 2.0 bus, the system will less likely to hit the bandwidth bottleneck. The new specification also inherits the current USB's Plug and Play and hot-swapping capability as well as providing backward compatibility for USB 1.1 hardware, allowing existing user base to upgrade seamlessly.

Do USB 2.0 & USB 1.1 hardware work interchangeably?
You may have heard that USB 2.0 is "backward-compatible" with USB 1.0/1.1 (Full-Speed USB). While that's true, USB 1.1 is also forward-compatible with USB 2.0. Whenever a system has USB 2.0 ports, you'll find the "Enhanced" USB controller in Device Manager, but you will also find two other USB controllers. These two to maintain backward compatibility to USB 1.1 devices. Each USB 2.0 host actually has 3 chips onboard. The USB controller routes signals to the correct controller chip depending on how a device is recognized. Where a device is physically plugged in has no bearing on how it is routed. All ports on a USB 2.0 motherboard can host any USB devices at all as long as the system and devices are healthy.

The vast majority of USB 2.0 devices will work on older PCs and Macs. None should flat-out fail unless there are other issues with the system. Hi-Speed USB devices will revert to Full-Speed operation when connected this way. Understand that Hi-Speed is at least ten times faster than Full-Speed in actual operation, so the speed difference is quite noticeable - unless you have never experienced Hi-Speed, of course.

When it comes to USB hub compatibility between USB 2.0 and USB 1.1, here some facts:

• A powered hub is always preferable to unpowered.
  

• USB hub ports are not as capable or flexible as real PC ports so it's best not to expect the world of them.
  

• USB 1.1 (obsolete) hubs will work fine on USB 2.0 ports, but they cannot utilize USB 2.0 capabilities. They will default to slower speeds.
  

• Hi-Speed and Full/Low-Speed USB devices can coexist nicely on USB 2.0 hubs. Connecting such a hub to a USB 2.0 port is recommended.
  

• USB 2.0 hubs can be used on older USB 1.1 computers.
  

• Although it is said that you can "cascade" up to 4 hubs, problems may start to arise after two hubs, it's best to minimize hub usage if possible.
  

• Many USB devices don't work well on hubs. Cameras, scanners and especially USB drives are known to have problems with hub connectivity.
  

• Remember that "active USB extensions" are really just one-port hubs.
  

Will USB 2.0 replace USB 1.1?
Not entirely, because many products such as generic keyboards, mice, joysticks and audio speakers do not require the faster speed of the new USB 2.0 technologies. Only bandwidth-hungry devices, such as web cams and high-capacity storage systems, will need all the speed. However, next-generation systems will come with USB 2 ports rather than USB 1.1.

How do I distinguish between a USB 2.0 and a USB 1.1 devices? New logos designed by the USB Promoter Group allow consumers to easily identify the new USB 2.0 products. The new colorful logo for USB 2.0 is labeled USB Hi-Speed, and the new logo for USB 1.1 is labeled with USB Basic Speed. However, most people won't miss it as manufacturers often label USB 2.0 READY Or 40 times faster than USB 1.1, on the boxes.

Will USB 1.1 devices run any faster on a USB 2.0 bus?
No. However, the new USB 2.0 archiclecture allows more high-speed USB 1.1 devices, such as web cams, audio devices, to share the bandwidth. Developers need to follow USB 2.0 spec in order to design higher speed peripherals that can take advantage of the extra bandwidth. USB 1.1 devices still operate at 12Mbps at full-speed and 1.5Mbps at low-speed on a USB 2.0 bus. Even though USB 1.1 devices won't run any faster, they can work alongside of USB 2.0 devices on the same bus.

What are USB Hi-Speed and USB Basic Speed logos?
These logos are part of USB Promoter Group's branding program that ensures the quality of USB products. The USB 2.0 certified products would display a blue, white and red logo, bearing the words Certified and Hi-Speed. The classic USB 1.1 certified products would display a black and white logo with the words USB and Certified.

Under a license from USB-IF, products must pass the compliance tests before manufacturers can use one of the two trademarked logos. The Promoter Group will take legal actions on manufacturers that label either logo on their products, which have not passed the tests.

What happen if a USB 2.0 devices are plugged into a USB 1.1 systems?
The entire bus under the USB 1.1 root hub will slow to 12Mbps. The operating system will probably notify the user about the sub-optimal configuration and recommend for a better course of action.

If several USB 1.1 hubs are connected to a USB 2.0 bus, then each of the USB 1.1 hubs will get a full 12Mbps bandwidth.

What is the max? Length of a USB 2.0 cable?
5m. however, if you cascade 5 hubs with 5m USB cables, this will allow you to connect a device 30m away.

What do I need to use a USB 2.0 device?
The requirement is similar to that of USB 1.1, but all components will have to be USB 2.0 compliant. A successful USB 2.0 connection requires a USB 2.0 host controller card, a USB 2.0 driver and a USB 2.0 peripheral.

How much will it cost to upgrade to USB 2.0?
Around $80 to $150. Currently, Orange Micro., Adaptec and IO Gear are shipping USB 2.0 PCI cards, some of which even have FireWire ports. Interestingly, almost all USB 2.0 PCI cards include an internal port, which is probably for connecting internal USB 2.0 IDE enclosure or USB 2.0 front panel.

Will USB 2.0 arrive on mobile computers?
Yes, but not in integrated solution on laptops. You will need a USB 2.0 Card Bus card. Orange Micro. is shipping USB 2.0 compliant 4-port Card Bus card. Eventually, notebook vendors will adapt to USB 2.0 technology, and we will see USB 2.0 ports on laptops. This transition won't happen until 2002 at the earliest.

Which operating systems support USB 2.0?
Microsoft has released the official USB 2.0 driver for Windows XP and Windows 2000. The version is 5.1.2600. The software is available on-line at Windows Update website. (If you don't have a USB 2.0 card installed in your system, Windows Update won't list the USB 2.0 driver as an update.)

The software company is still considering USB 2.0 support for Windows ME, but it already has decided not to bring USB 2.0 to Windows 98 and Windows 98 SE. If you have Windows 98, you will have to rely on 3rd party USB 2.0 support from USB card manufacturer.

Do USB 1.1 cables work with USB 2.0 devices?
Ideally, yes. USB 2.0 architecture uses the same cables and connectors as USB 1.1 compliant products. Unfortunately, only 3 out of 11 cables on the market are certified as USB 1.1 compliant. You may run into the cables that cause problems connecting high-speed peripherals. To avoid negative user experience, most vendors include USB 2.0 compliant cables with their USB 2 PCI cards and peripherals.

Database Tips

What is database?

A database is a collection of related data stored in an efficient and compact manner. The word “efficient” means that stored data can be accessed very easily and quickly.

Similarly, the word “compact” means that stored data takes up as little space as possible. In the above definition of database, the phrase “related data’ is used. It means that a database contains data or information about a particular topic such as:

• Database of employees that contains data of employees of an organization or department.
  

• Database of students that contains data of students of college or university.
  

A database holds related data as well as description of that data. For this reason, a database is also defined as a self describing collection of integrated records. The description of data is known as the system catalog or data dictionary or metadata. For example when a table of a database is designed, the data type, size, format and other descriptions of fields are specified. This is an example of metadata, which describes the properties of data to be stored into fields of table.

The data of any organization is its integral part. The data is very important for developing new products and their marketing. The data must be accurate and available when needed. This is the reason that all organization must organize and manage their data into database. The databases are used for variety of purposes in as organization. For example, when you purchase goods from your local supermarket, the checkout assistant will pass the purchased product through a scanner device known as bar code reader. This device will read the bar code printed on the product and gives the accurate price of the item. Actually, the bar code reader is accessing the database, which contains the information about the products. The bar code reader is linked to a database application program, which uses the bar code to access price of item. The database program automatically updates the database. The assistant can also check whether a required item is in stock by running the database application program. Similarly, you can purchase goods using your credit card. Your credit is checked by a card reader linked to a computer system. In this case, there is a database somewhere that contains information about your credit. Almost all organizations and government departments of every country in world use database to maintain their records. Some examples of large databases that have been developed around the world are:

• When you draw amount from bank through ATM card, you are accessing the database; your account is accessed and checked through auto teller machine. When you draw some amount from your account, your record in the database is automatically updated immediately.
  

• When you visit your local library, there may be a computerized database containing details of the books in the library. There will be a computerized index, which allows you to find a book based on its title, its author’s name etc.
  

• The meteorological organization contains databases having information about current and previous meteorological data. The meteorological department is totally dependent on the meteorological data.
  

A database may be generated and maintained manually or it may be computerized. The library card catalog is an example of a database that is created and maintained manually. On the other hand, a computerized database may be created and maintained either by using application program, which is developed specifically for that purpose or by a database management systems.

Scanner Cleaning Tips

Digital scanner is a very popular input device. Its main purpose to translate images and text printed on the paper into electronic form that can be processed and stored by the computer.

• To clean the scanner first unplugs your system power from the electrical outlet.
  

• Always clean the glass of your scanner with any optical surface cleaning fluid.
  

• This process should be done after every three months if you want to save your scanner life.

SCSI Disk

1. Disk SCSI (Small Computer System Interface) IDE with similar organizations in addressing.
2. Differences in the tool interface capable of transferring data in high speed.
3. High-speed transit, is a standard for computers.
4. UNIX from Sun Micro systems, HP, SGI, Machintos, Intel, especially computer-server computer network, and vendor-other vendor.
5. SCSI is actually more than just a tool interface hard disk.
6. Each device has a unique ID as a media introduction by the SCSI.
7. SCSI is a bus as capable as a checker to 7 equipment such as:
   

• Hard
• CD-ROM
• CD-Recorder
• Scanner music, n traveling.

SCSI Disk Version

Computer Evolution and Performance Part 12

Solutions
- Increasing the number of bits in one time

• Create greater DRAM

- Changing the interface DRAM

• Cache

- Reduce frequency access memory

• Cache more complex and is located on the chip

- Improve the bus system

• High speed buses

• Hierarchy of buses

I / O Devices
- The device needs for operation of I / O
- Need Throughput data that is large enough
- Processor can handle this task
- Problems in the transfer of data
- Solution:

• Caching

• Buffering

• High-speed interconnection buses

• More elaborate bus structures

• Multiple-processor configurations

Typical I / O Device Data Rates


The key: balance
- Processor components
- Main memory
- I / O devices
- Interconnection structures

Computer Evolution and Performance Part 7

Speed generation - Generation Computers


Microelectronics

• Literally - "small electronics".
• Computer formed from the gate collection, a collection of memory and interkoneksinya.
• Can be made with the semiconductor.
• Example: silicon wafer (Silicon wafer).
  

Generation of Computer

• Vacuum tube - 1946-1957.
• Transistor - 1958-1964.
• Small scale Integration - on 1965.
• Up to 100 devices on a chip.
• Medium scale Integration - to 1971.
• 100-3,000 devices on a chip.
• Large scale Integration - 1971-1977.
• 3,000 - 100,000 devices on a chip.
• Very large scale Integration - 1978 to date.
• 100,000 - 100,000,000 devices on a chip.
• Ultra large scale Integration.
• Over 100,000,000 devices on a chip.

Computer Evolution and Performance Part 6

Transistors

• Replacement vacuum tube.
• More small. - More light.
• Need more power low.
• Solid State devices.
• Made from Silicon Silicon (Sand).
• Found in 1947 in Lab.Bell
• William Shockley, et al.
  

Transistor Images


Transistor-Based Computers

• Second-generation machine.
• NCR & RCA create a small transistor machines.
• IBM 7000 series.
• DEC (Digital Equipment Corporation)
• 1957

>> Removing the type of computer PDP-1