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Maxtor D540X-4K manual Latency time and thus increases data throughput

Models: D540X-4K

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Basic Principles of Operation

￿￿￿￿￿￿￿2GTHQTOCPEGIn a drive without￿$GPGHKVUDisCache, there is a delay during sequential reads because of the rotational latency, even if the disk actuator already is positioned at the desired cylinder. DisCache eliminates this rotational latency time (7.14 ms on average) when requested data resides in the cache.

Moreover, the disk must often service requests from multiple processes in a multitasking or multiuser environment. In these instances, while each process might request data sequentially, the disk drive must share time among all these processes. In most disk drives, the heads must move from one location to another. With DisCache, even if another process interrupts, the drive continues to access the data sequentially from its high-speed memory. In handling multiple processes, DisCache achieves its most impressive performance gains, saving both seek and latency time when desired data resides in the cache.

The cache can be flexibly divided into several segments under program control. Each segment contains one cache entry. A cache entry consists of the requested read data plus its corresponding prefetch data.

The requested read data takes up a certain amount of space in the cache segment. Hence, the corresponding prefetch data can essentially occupy the rest of the space within the segment. The other factors determining prefetch size are the maximum and minimum prefetch. The drive’s prefetch algorithm dynamically controls the actual prefetch value based on the current demand, with the consideration of overhead to subsequent commands.

￿￿￿￿￿￿GCFHead￿CPFand￿%[NKPFGTcylinder skewing￿5MGYKPIin the Maxtor D540X-4K AT hard disk drives minimize

￿*latency time and thus increases data throughput.

GCFHead￿5MGYKPIskewing reduces the latency time that results when the drive must switch read/ write heads to access sequential data. A head skew is employed such that the next logical sector of data to be accessed will be under the read/write head once the head switch is made, and the data is ready to be accessed. Thus, when sequential data is on the same cylinder but on a different disk surface, a head switch is needed but not a seek. Since the sequential head-switch time is well defined on the Maxtor D540X-4K drives, the sector addresses can be optimally positioned across track boundaries to minimize the latency time during a head switch. See Table 5-2.

￿￿￿￿￿￿￿%[NKPFGTCylinder￿5MGYKPIskewing is also used to minimize the latency time associated with a single- cylinder seek. The next logical sector of data that crosses a cylinder boundary is positioned on the drive such that after a single-cylinder seek is performed, and when the drive is ready to continue accessing data, the sector to be accessed is positioned directly under the read/write head. Therefore, the cylinder skew takes place between the last sector of data on the last head of a cylinder, and the first sector of data on the first head of the next cylinder. Since single-cylinder seeks are well defined on the Maxtor D540X-4K drives, the sector addresses can be optimally positioned across cylinder boundaries to minimize the latency time associated with a single-cylinder seek. See Table 5-2.

Maxtor D540X-4K 20.4/40.0/60.0/80.0 GB AT 5-11

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Maxtor D540X-4K manual Latency time and thus increases data throughput
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D540X-4K specifications

The Maxtor D540X-4K is a notable hard disk drive that has made its mark in the world of computer storage solutions. Launched in the early 2000s, this drive was known for its high capacity and reliable performance, making it a popular choice among consumers and businesses alike.

One of the main features of the D540X-4K is its generous storage capacity. With a range of models available, users could select from configurations starting at 40GB to larger sizes, accommodating a wide variety of storage needs. This capacity was particularly advantageous during an era when digital media was rapidly expanding, allowing users to store everything from documents and photos to videos and applications without running out of space.

The D540X-4K utilizes an IDE (Integrated Drive Electronics) interface, also known as PATA (Parallel ATA), which ensures compatibility with a broad spectrum of computers. This interface was standard at the time, making the drive accessible to a wide user base. The drive also supports ATA-100, providing data transfer rates of up to 100 MB/s, which was impressive for its time.

In terms of performance, the drive operates at a speed of 5400 RPM, which, while not the fastest in comparison to modern solid-state drives, provided a suitable balance of speed and efficiency for the average user’s needs. This rotational speed ensured decent read and write times for everyday applications, making it a reliable option for personal computing.

Another characteristic of the D540X-4K is its advanced data protection features. The drive was equipped with Maxtor's unique Shock Protection Technology, which helps protect the drive’s internal components from damage due to shocks or drops. This feature contributed to increased reliability, especially for users in mobile or high-traffic environments.

The Maxtor D540X-4K also incorporates a Cache Buffer, which enhances performance by temporarily storing frequently accessed data. The cache sizes varied across models, with options of 2MB or more, aiding in quicker data retrieval and overall improved system responsiveness.

In summary, the Maxtor D540X-4K is a hard drive that stands out for its storage capacity, compatibility, and protective features. Even today, it serves as a reminder of the evolution of data storage technologies, as it laid the groundwork for the high-capacity drives we utilize in modern computing. Its legacy continues to influence new technologies while reflecting the needs of the early digital era.