Error Correcting Code Operation

2 System Board

Devices on the Processor-Local Bus

Each bank that is used must contain a pair of identical modules: the same speed (60 or 70 ns), the same width (32-bit or 36-bit), and the same technology (extended data out, EDO, or fast page mode, FPM). Different banks can contain different speed modules (but the computer will work at the speed of the slowest bank). Different banks can contain different width modules (but parity and error correcting codes, ECC, are not enabled if any 32-bit width pairs of modules are used). Different banks can contain different technology modules.

The following table indicates the recommended capacities of main memory.

Operating System	Minimum Memory Capacity	Recommended Memory Capacity

Windows 3.11	4 to 8 MB	12 to 16 MB

Windows 95	8 MB	16 to 24 MB

Windows NT	12 MB	24 to 32 MB

OS/2	4 to 8 MB	16 MB

The Setup program automatically detects which memory module capacity, speed, and type is installed in each bank. Individual pages of memory can be configured as cacheable or non-cacheable by software or hardware. They can also be enabled and disabled by hardware or software.

Error correcting code (ECC) is available when using 36-bit memory modules. The original 32-bit modules must be removed so that the memory is populated exclusively by 36-bit modules. The appropriate field must be set in the Memory sub-menu of the Configuration menu of the Setup program.

Using ECC, a single bit error in any 72-bit line of memory (64 data bits plus 8 parity bits) is corrected automatically and transparently. A double bit error causes an NMI to be generated, and the computer to be halted.

If more than two bits are faulty within any given 72-bit line, the effect is the same as it would have been without error correction. The effect of executing a faulty instruction is always unpredictable, and might cause the program to ‘hang’. The effect of reading a faulty data word is often similarly unpredictable, but can sometimes be tolerated (for instance, it might merely appear as a corrupted pixel on a video display).

An extra delay is introduced in the chip set while it is performing the ECC conversions, so causing ECC memory to have a slower access than non-ECC memory. Moreover, ECC memory modules are available only in 70 ns FPM technology.

Vectra VL 5/xxx 5 specifications

The HP Vectra VL 5/xxx was a series of desktop personal computers introduced by Hewlett-Packard in the mid-1990s. These machines were designed for both business and professional environments, making them suitable for a range of applications from basic office tasks to more demanding computing needs. This series played a significant role in HP's efforts to strengthen its market presence in the PC sector during a time when competition was intensifying.

One of the standout features of the HP Vectra VL 5/xxx line was its versatility. The series included various configurations designated by the '5/xxx' nomenclature, which indicated different performance levels and specifications. The performance was driven primarily by Intel Pentium processors, widely acclaimed for their reliability and efficiency. This allowed users to choose a model that suited their specific requirements, whether for everyday tasks or more resource-intensive applications.

In addition to its strong processing capabilities, the Vectra VL 5/xxx featured advanced graphics support, which was critical for visual applications and presentations. Many units in this series came equipped with onboard graphics capabilities that supported a range of resolutions, enhancing the user experience in both standard office environments and more creative settings.

Storage options were another highlight of the HP Vectra VL 5/xxx series. The machines typically featured a variety of hard drive configurations, allowing for ample data storage. Some models included the option for expanding storage through additional hard drives or external devices. Coupled with considerable RAM options, these machines ensured smooth multitasking and efficient performance across various applications.

Connectivity was also a core aspect of the Vectra VL 5/xxx. The systems typically included multiple USB ports, parallel and serial ports, and integrated networking capabilities. This made it easy for businesses to integrate the Vectra machines into their existing infrastructure, facilitating seamless interaction with peripherals and networks.

In terms of design, the HP Vectra VL 5/xxx series presented a robust yet compact form factor, which was ideal for office environments with limited space. Additionally, HP emphasized the reliability and serviceability of these machines, which included easy access to internal components for maintenance and upgrades, thereby extending the product life cycle.

Overall, the HP Vectra VL 5/xxx line offered a balanced combination of performance, flexibility, and reliability, making it a solid choice for organizations looking to leverage computing power for a range of professional applications. The series embodied HP's commitment to delivering quality and innovation in the ever-evolving landscape of personal computing.