Wireless technologies

Wifi 802.11 $44, 100Mb, 100M

WiFly $44, 100Mb, 100M

SHDC memory with WIFI $50

ZigBee 802.15.4 $20, 250 kb, 100M - 1 mile
Bluetooth 802.15.1 < $20, 3Mb, 100M
Cellular $64 + sevice

2G, 3G
GSM, GPRS, EDGE, W-CDMA, UMTS, TDMA, CDMA, CDMA2000 1xRTT, CDMA2000 1xEV-DO, and CDMA2000 1xEV-DV

4G
must have target peak data rates of up to approximately 100 Mbit/s for high mobility such as mobile access and up to approximately 1 Gbit/s for low mobility

Comments

Post a Comment

Popular posts from this blog

Sites, Newsletters, and Blogs

BLOGS Java.net Weblogs Martin Fowler's blog Paul Graham Ruminations of a Programmer Form Follows Function Newsletters Core Java Tech Tips Enterprise Java Tech Tips JavaSpecialists.EU TheServerSide.com Sites Java.net Today Hot Java Sites CSS Zen Garden Evernote Hacker News Pragmatic Programmer
Read more

Oracle JDBC ReadTimeout QueryTimeout

If a query exceeds the oracle.jdbc.ReadTimeout without receiving any data, an exception is thrown and the connection is terminated by the Oracle driver on the client. Unfortunately the session will still be queued on the database and continue to wait for locks, hold any current locks, and complete any DML/PL*SQL procedures that are pending on the server-side of the orphaned connection. If an application, on a another connection, due to ReadTimeout exception, retries DML/PL*SQL  which requires locks, those queries will queue behind the initial DML/PL*SQL. This will increase the workload exacerbating the situation. On applications with retries, this can be observed by querying the v$session table  or gv$session on RAC and noting new sessions started periodically based on the ReadTimeout interval. The sessions may often have the same SQL_ID and/or SQL_HASH_VALUE. If stmt.setQueryTimeout(Seconds) is issued and the statement exceeds the timeout, it will attempt to cancel the associated
Read more