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here are the details of the n91 micro-drive.
The drive is manufactured by Hitachi, I shall remind you that it has purchased the division of IBM, which claimed the title of pioneers in the field of these devices. The name of the line-up was corresponding - Microdrive. Nokia N91 features a new model of this drive – Microdrive 3K4-4. Its characteristics are quite good and to some extent can be compared to flash memory:
Cache buffer 128 Кб
Speed 3600 rpm
Latency Average – 8.33 ms
Media Transfer Rate – 57.1-97.9 (max. Mbits/s)
Sustained Data Rate – 4.3-7.2 (Mb/s)
Seek time (read, typical) – 12 ms, track to track – 1 ms, full track – 22 ms
Limit of 300000 cycles of on/off
Those, who are fond of digging in the internal part of phones, will be surprised by the fact that the hard drive, featured in Nokia N91 has the dimensions of 32х24 mm, rather than the standard 42х36 mm. The explanation lies in use of CompactFlash II connector by most of the companies, incorporating Microdrive disks into their solutions, though Nokia declined the idea of using a disk in the standard shell. It means that the hard drive, presented here is an analogue of Microdrive 3K4-4, but it differs in shell, which was replaced by a special socket on Nokia N91 chip (located lower than the camera’s module, but above the battery, exactly under the safety casing). The developers applied here not only floating support for the disk, but also a special casing, which amortizes all blows. From above the disk is also protected by a soft rubber cover, which deflects frontal blows and lowers noise level at the same time. To tell the truth, one can rarely hear the disk itself – only in cases when you hold the handset in your hands do some inhumane experiments, e.g. open the rear lid and instantly pull out the battery. The interface connector is designed specially for this model and is aimed at lowering the place, occupied by the hard drive.
The cover has a pressure sensor, so once the battery's cover is removed, the disk automatically turns off. This process takes up to one second. Another precaution is acceleration sensor – in case the device is falling from a height more than 1 meter, the hard disk switches off, so it may avoid a certain amount of damage, since exactly when turned on, the disk is vulnerable to mechanical effects. For good reason we didn’t try to carry out stress tests, since all throws could hurt the screen, rather than the hard drive, because protection level featured in Nokia N91 is higher than in all other devices using Microdrive. There are some numbers regarding durability of iPOD Mini – after a certain period operation most of devices work fine, and no wonder about it, as here the developers also used the system, applied to N91.
Temperature conditions, stated by the manufacturers are 0-70 degree centigrade. At the same time the User guide features the fact that one should observe the temperature conditions, otherwise the hard disk will just switch off, though no exact numbers are stated. Taking into account Russia being a country with cold climate, we decided to test the model in the conditions of temperature below zero. In order to carry out this test, we used a freezer with the handset inside it. At five degrees below zero the device worked without any visible errors – it kept playing back music and even didn’t turn off. At -10 everything seemed to be the fine, though at twelve degrees below zero, the phone refused to work with hard drive. In practice this means that the handset endures any winter conditions and temperatures, as you will carry it only your pocket. However the shell remains very cold – metal is metal anyways.
Each manufacturer tries to tie the amount of external memory to a certain number of tracks which can be stored on the handset. At this they make a footnote that all calculations were carried out on the basis of some exact length of each track etc. The reason of all these complicated actions is concealed from me, since stating storage size is already more than enough. I doubt whether many remember how many space requires this or that album or all tracks in sum. In short, there is no need in providing users with such information.
Energy consumption is an essential parameter for a hard drive and here Nokia N91 is riding high. It was very easy to check how much time the device will last with network part turned on and constant tracks playback. We uploaded around 900 songs with mp3 extension, which totaled 3.7 Gb, set them for random playback (this prevents cache buffer use), plugged in headphones and adjusted volume to the middle. In these conditions the device managed to work around 10 hours and this is really worthy performance, comparable with most of the modern MP3 players life time, which use the same hard drive (e.g. Creative MuVo2 4Gb with announced 14 hours of life time, though in practice it lasts not more than 11-12 hours). | 
2nd May 2006, 02:01
! u can get N91 for 29k or so !
