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Hard Drive Capacity Vs. Available Disk How big is that drive? The capacity
rating for hard drives sold by GOLDENRAM is in accordance with the
rating supplied by the hard drive manufacturer. The actual
available hard disk space will vary according to a number of
factors. OS Efficiency The single most
significant factor is the Operating System or OS. Different
operating systems use different amounts of disk space for the
basic operation and maintenance of the information stored on the
drive. Microsoft's DOS is one of the least efficient operating
system as far as hard drive usage is concerned. DOS can use more
than 20% of a disk drives space for it's partition table, FAT,
and boot record. Other operating systems use different techniques
to maintain the hard drive and are more efficient in their hard
drive space usage. However, in the worst cases, a 1 gigabyte
drive has it's available space reduced to 800 megabytes by the
simple application of a DOS partition and format. Even though the
drive has no user files on it. Parameter Efficiency Another variable
is the hardware configuration. A drives maximum capacity is
determined by a set of parameters that describe how the drive and
computer will interact. In some cases, a single increment change
to a single parameter can change the total capacity of the drive
by over 100 megabytes. Some hard drive controllers and some
computers are not capable of utilizing the correct parameters for
a particular drive. In these cases, an automatic or manual
adjustment of the parameters must be made. These adjustments may
not yield the full capacity of the drive. 10^6 vs. 1024^2 The final factor
determining a drives capacity is how the drive is rated by the
manufacturer. Some drive manufacturers have determined that 1
megabyte is the equivalent of 1 million bytes. Other
manufacturers call 1 megabyte the equivalent of 1024 bytes times
1024. Computers store information in RAM and utilize hard drive
space according to the second rating system because of the binary
basis of computers. By using the '1 million bytes per megabyte'
rule, a drive can be described as being larger. Here's a table
showing some comparisons of different drive sizes using both
rating systems.
*Assuming 1
gigabyte is equal to 1000 megabytes The drive
ratings are the most confusing since the rating system is
subjective. DOS normally reports megabytes available using the
1024 * 1024 rating system. Both rating systems result in the same
storage capacity. One Byte of data uses one Byte of hard drive
space regardless of how many Bytes per megabyte the manufacturer
says there are. What does all this mean to the end user? Well, on a small
drive, say in the 210MB range and under worst case conditions.
The actual available hard disk space may be as low as 180MB. An
apparent loss of 30MB. On a 2 gigabyte drive and under similar
worst case conditions the loss can be as much as 500 megabytes!!!
That means less than 1.5 gigabytes of available space. |