Intel’s Pentium 4 processors featuring security feature Execute Disable Bit targeted at mainstream market segment with appropriate price-points have finally hit the stores, but not everywhere in the world.

Execute Disable Bit a security feature that protects certain system memory data regions from insertion and execution of potentially harmful code; the technology is also referred as NX-bit and EVP and works only in conjunction with Windows XP operating systems that feature Service Pack 2. Execute Disable bit allows the processor to classify areas in memory by where application code can execute and where it cannot. When a malicious worm attempts to insert code in the buffer, the processor disables code execution, preventing damage or worm propagation. To provide end-to-end no execute (NX) coverage, To provide end-to-end no execute (NX) coverage, Intel already released XD-enabled chips for workstations, and server products beginning in late Q3 2004.

So far only numerous Intel Celeron D processors for Socket 775 infrastructure as well as Intel Pentium 4 processor 570J clocked at 3.80GHz – the top-of-the-range offering – supported the Execute Disable Bit. Few days ago Intel Pentium 4 processor 530J (3.00GHz) with EDB emerged in retail stores in Tokyo, Japan, for approximately $205, Akiba PC Hotline web-site reports.

Intel’s official price-list currently includes a number of Intel Pentium 4 chips with 800MHz bus and 1MB L2 cache supporting EDB with clock-speeds ranging from 2.80GHz to 3.80GHz and pricing from $163 to $637, respectively. However, apart from the top model 570J, there were no EDB-enabled Pentium products in the stocks of the USA and European web-stores at press-time, according to X-bit labs’ probes using various price-search engines. Computer maker Dell Inc.’s web-site did not detail whether the systems features EDB-enabled chips or not.

All the Intel microprocessors with the “-J” designator have Execute Disable Bit (EDB) technology. BIOS and operating system of the computer system should also support the tech to enable it.

Intel released EDB-enabled x86 chips for workstations and server products beginning in late Q3 2004. The company said in early October, 2004 its desktop products were shipping to the market, with system availability in Q4 2004. Intel promised to start shipping mobile processors with EDB tech in late Q4 2004, with system availability in Q1 2005.

Advanced Micro Devices, another leading maker of microprocessors, has been shipping AMD Opteron and AMD Athlon 64 central processing units with no execute bit (NX-bit) support since April and September, 2003, respectively. Intel first introduced its XD-enabled processor – the Itanium – in 2001.