PortableComputing: February 2015

Wednesday 25 February 2015

Information about Bluetooth (Portable computing)

Bluetooth is a wireless technology standard for exchanging data over short distances (using short-wavelength UHF radio waves in the ISM band from 2.4 to 2.485 GHz^[3]) from fixed and mobile devices, and buildingpersonal area networks (PANs). Invented by telecom vendor Ericsson in 1994,^[4] it was originally conceived as a wireless alternative to RS-232 data cables. It can connect several devices, overcoming problems of synchronization.

Bluetooth is managed by the Bluetooth Special Interest Group (SIG), which has more than 20,000 member companies in the areas of telecommunication, computing, networking, and consumer electronics.^[5] The IEEEstandardized Bluetooth as IEEE 802.15.1, but no longer maintains the standard. The Bluetooth SIG oversees development of the specification, manages the qualification program, and protects the trademarks.^[6] A manufacturer must make a device meet Bluetooth SIG standards to market it as a Bluetooth device.^[7] A network of patents apply to the technology, which are licensed to individual qualifying devices.

Information about WiFi (Portable Computing)

The Wi-Fi Alliance defines Wi-Fi as any "wireless local area network" (WLAN) product based on the Institute of Electrical and Electronics Engineers' (IEEE) 802.11 standards".^[1] However, the term "Wi-Fi" is used in general English as a synonym for "WLAN" since most modern WLANs are based on these standards. "Wi-Fi" is a trademark of the Wi-Fi Alliance. The "Wi-Fi CERTIFIED" trademark can only be used by Wi-Fi products that successfully complete Wi-Fi Alliance interoperability certification testing.

Many devices can use Wi-Fi, e.g. personal computers, video-game consoles, smartphones, digital cameras, tablet computers and digital audio players. These can connect to a network resource such as the Internet via awireless network access point. Such an access point (or hotspot) has a range of about 20 meters (66 feet) indoors and a greater range outdoors. Hotspot coverage can comprise an area as small as a single room with walls that block radio waves, or as large as many square kilometres achieved by using multiple overlapping access points.

Tuesday 24 February 2015

The number of significantly different CPUs and operating systems used on the desktop today is much smaller than in the past. The dominance of the x86 architecture means that most desktop software is never ported to a different CPU. In that same market, the choice of operating systems has effectively been reduced to three: Microsoft Windows, OS X, and BSD Unix/Linux. However, in the embedded systems market, portability remains a significant issue.

International standards, such as those promulgated by the ISO, greatly facilitate porting by specifying details of the computing environment in a way that helps reduce differences between different standards-conforming platforms.