Even though Firewire was initially introduced by Apple PC, it was later standardized by IEEE 1394. It has become one of the most appropriate serial interfaces between computers and high speed peripherals. Peripherals using Firewire bus use direct memory access (DMA), implying that they can get into system memory without CPU notice. As such, the hardware can either read or write synchronously or isochronously into the system memory. All that is needed is a DMAC (DMA controller) which includes suitable application to enable the devices to read or write to a particular area of the IEEE 1394 hardware storage space (Carvey, 2007, p.91).
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There are various advantages which can be achieved by employig DMA in hardware without OS intervention. It ensures data transfer without dependence on processors making DMA transfers simpler than those intervened by OS. As processor is not occupied, DMA transfers allow the processor to perform other tasks. There are improved speeds of data transfer with DMA hardware as the transfer starts immediately the hardware ascertains that the data is all set instead of waiting until the data attains an appropriate level of transfer as with programmed hardware. This shows such hardware enables high speed and small latency data movements (Intelligent Instrumentation, n.d). However, there are security risks which can arise when unreliable hardware is attached to IEEE 1394 bus. Such hardware may use DMA in reading or moddifying memory without OS or CPU awareness. Such risks can be addressed by disabling DMA device recording between the device’s storage and IEEE 1394, deactivating the overall Firewire and implementing hardware capable of mapping buffer memory to the IEEE 1394 storage (Jakobsson & Ramzan, 2008, p.87).
In regard to security risks imposed by DMA hardware, USB is better in preventing modifications that can result due to connection of unreliable hardware. USB transfer occurs with intervention of OS and therefore, the CPU is always alert in case of any mischievous operations in the memory. In this way, it is possible to detect and rectify in real-time security risks through use of USB hardware.
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