The capacity of the hard disk drive (HDD) is
getting bigger and bigger, solid state drive (SSD) are becoming popular while
hybrid hard drive combining the strength of HDD and SSD also promises to have a
future which is not less attractive.
HDD couldn’t fully recover after the
historic flooding in Thailand, while SSD also had a strong development and
became popular in the high-class laptop line. Besides, the fact that the
leading hard drive manufacturers in turn announced the models of HHD also had a
part in creating the diversity of the market.
Here are some basic concepts, advantages
and disadvantages of the above devices so as to help you having the best
decision for personal need.
Hard disk drive (HDD)
Basically, the architecture inside the HHD
includes platters stacked together in vertical axis. Each platter is divided
into many concentric circles called track. Each track is also divided into many
segments called sector. The top sectors combine together to form cluster and
the data is saved on each cluster. When there is a data access request, the
read/write heads will move through the disk surface (horizontally) to read or
write data on each cluster.
The
architecture inside the HDD
Therefore, the number of platter’s
revolution (revolution per minute - rpm) and the moving speed of the read/write
heads will affect significantly the hard drive’s performance. Moreover, each
company has its own technology to improve the performance, increase endurance
or stability of the hard drive during used process.
Currently, the highest access speed of the
hard drive can reach 200 MB/second and the random access time is from 5-8ms. Calculating
based on the capacity and cost (on each gigabyte), HDD is still the first
choice. Most of today’s hard drives use SATA 3.0 interface (6 Gb/second) and
the capacity reaches the 4TB “mark” (equivalent 4000 GB).
Solid state drive (SSD)
Compared with HDD, solid state drive (or SSD)
has dominance in data access speed (read/write), endurance and the better
shock-resistant ability, cooler operation due to not having moving parts.
Therefore, your data will be better protected when the computer is dropped or
impacted.
SSD
Vector of OCZ is currently one of the fastest SSDs.
About memory technology, SSD is divided in
to 2 kinds of which are using flash NAND SLC (single level cell) that contains
1 bit of data on each cell and using flash NAND MLC (multilevel cell) that
contains 2 or more data bit on each cell. As compared with flash SLC, MLC has low
endurance, slower access speed and be normally used in SSD common line, while flash
NAND SLC has higher endurance, faster access speed and be used in advanced SSD.
Besides, SSDs also support TRIM technology
in order to prevent the decrease in read/write speed after a period of use.
However, you also need to notice the OS versions supported by TRIM, which are Windows
7, Windows 8, Windows 2008 R2, Mac OS X Snow Leopard (10.6.6), Lion (10.7),
OpenSolaris versions and FreeBSD 8.2.
Common SSDs still use SATA 3.0 interface (6
Gb/second) while advanced SSDs use PCI Express interface, access speed,
endurance and reliability of which are many times higher than the common SSD.
The SSD’s highest data access speed can reach 550 MB/second; almost reach the
critical threshold of 6 Gb/second of SATA 3.0 interface, random read/write
performance is about 80,000/65,000 data (4KB) in/out per second (IOPS).
Though the price of SSD decreased a lot in
the pass time, but the rate of price/capacity is still very high as compared
with HDD. Besides, because of the use of flash memory to store data so the
capacity of the SSD in some part is more ‘humble” than the HDD. Despite having
higher endurance than HDD, SSD can “die suddenly” without any forewarning. Therefore,
users need to back up the important data, personal info when there is error in
the hard drive.
Hybrid hard drive (HHD)
Appeared in recent years, HHD hay hybrid
hard drive combines the strengths of both SSD and HDD; higher access speed, at
the same time having larger storage capacity and the suitable price for
majority of users.
The
data which always needs fast access is saved in the flash memory while the data
which is not used regularly will be saved on the platters of the HHD.
The operation mode of the HHD is similar to
the hybrid graphics technology applied on some current personal computer line
(laptop, desktop). The data which is always used and needs fast access is saved
in the flash memory while the data which are not accessed regularly will be
saved on the platters of the hard drive. Users don’t need to choose and
determine where the data locates; instead, storage processing algorithms on
hard drive’s firmware will define what data is saved at flash SSD memory and
what is saved on the hard drive.
Momentus XT SSHD of Seagate use Adaptive
Memory logical buffer memory technology while Toshiba, Western Digital, also
has the same memory technology but instead, that’s the combination of SSD and
HDD in the same physical hard drive. Despite using what technology, processing
algorithms still play an important role in monitoring the level of using files
of the OS and software to decide whether to save them in SSD or HDD.
Momentus
XT, Seagate‘s HHD applies Adaptive Memory logical buffer memory technology.
At first, when there’s nothing on flash
memory, the access speed of the HHD will be the same as HDD, but after a period
of use, the access speed will gradually improve, and the performance increase
conspicuously. The test of American PCW on Seagate Momentus XT 750GB HHD with
8GB SSD shows that after 6 time testing, startup time of the system reduce
gradually from 35 seconds down to 31 seconds, WorldBench 7 mark increases from
112 to 116. The improvement in the startup time of the system reaches 12%,
WorldBench 7 mark increases 4%. In long term of considering, HHD will little by
little increase the overall performance of the system during using process.
Which choice is right for you
As mentioned above, considering the rate
between capacity and cost, the HDD is still an attractive choice. The hard
drives with capacity of 500GB or less will be a suitable choice for home and
office user for the demand of simple study, work and entertainment. The hard
drive with the capacity of over a terabyte will be suited for data center or
home theater PC (HTPC) which need large storage space.
SSD
market always has fierce competition among brands.
SSD with the outstanding advantages in
access speed and good shock-resistant ability will be suitable for users who
are usually on the move. However, due to the high cost of manufacturing the
flash memory, so the companies usually limit the SSD capacity to create a
reasonable price. For example, SSD with 128 GB capacity has the average price
of 125USD, as equal to the price level for 3.5-inch HDD 2TB in capacity for
desktop or 2.5-inch HDD 1TB in capacity for laptop. If using laptop, you should
choose SSD 128 or 256GB in capacity depending on the nature of the work, while
to desktop, you should use SSD 128 GB in capacity as a system partition
(partition used to install OS and software) while still using the HDD to store
data.
Modern HHD is designed in 2.5-inch
standard, suitable for laptop thanks to compactness and faster speed rather as
compared with HDD, but still guarantee the large storage capacity. Seagate,
Samsung, Toshiba and Western Digital in turn announce their HHD models.
