Full Circle Magazine FR

This hard drive is a 2.5” unit for laptops, that, at approximately 8mm in height, should fit most laptops and netbooks. It combines a standard platter 1000 GigaByte hard drive, and an 8 GigaByte Solid State Drive (SSD), both integrated into a hybrid unit that Toshiba calls a Solid State Hybrid Drive (SSHD). The SSD part is a smaller but much faster storage space, and is used as a cache to access data at higher speeds than would normally be possible with a platter drive. The cost is lower than would be possible with a pure SSD drive of similar capacity, though higher than a platter drive. Data management is performed by the hard drive circuitry, with no intervention needed (nor indeed possible) from the operating system. This is a departure from Apple’s Fusion Drive, where the OS itself manages data transfers between the SSD and the platter parts of the drive. I tested this unit in an Acer Aspire AO-722. This 11.6” netbook has an AMD C-60 64-bit processor, and originally came with a 320 GigaByte platter drive. When upgrading to an SSD drive in search of more speed, the small case dimensions meant that the platter drive had to go to make space for the replacement SSD drive, a Crucial M4. This worked fine, system and application boot times went way down and performance was in line with what could be expected from a lightweight computer with a fast drive: the limiting factor was now the processor, not the hard drive. However, I had achieved this at the expense of losing disk space, since the Crucial unit holds only 64 GB. Other SSD drives were available, but at extra expense. Though their prices have gone down during the last year, users should still expect to pay about $1.00 per GigaByte: large SSDs in excess of 500 Gigabytes may be worth more than the computer itself! If the hybrid drive holds its promises, I may be able to get the best of both technologies within the limited physical space available for this small computer.

La taille de ce disque dur, pour portables, est de 2,5 pouce. Son hauteur est d'environ 8mm et, par conséquence, il devrait aller dans presque tous les netbooks et portables. Il combine un disque dur standard de 1000 Go et un SSD de 8 Go, les deux faisant partie d'une unité hybride que Toshiba appelle un Solid State Hybrid Drive (SSHD). Le composant SSD est un espace de stockage plus petit, mais beaucoup plus rapide et s'utilise comme un cache pour accéder aux données à des vitesses plus élevées qu'atteintes normalement avec un disque dur standard. Le prix est plus bas que celui d'un SSD pur de capacité similaire, mais plus élevé que pour un disque dur standard. La gestion des données est faite par les circuits du disque dur et aucune intervention du système d'exploitation n'est nécessaire, ni en fait possible, alors que, dans le Fusion Drive d'Apple, le système d'exploitation même gère les transferts de données entre les parties SSD et disque dur du disque hybride.

J'ai testé ce SSHD dans un Acer Aspire AO-772. C'est un netbook de 11,6“ avec un processeur AMD c-60-64-bit qui, au départ, avait un disque dur standard de 320 Go. Quand j'ai fait une mise à niveau vers un disque SSD, car il me fallait plus de vitesse, les petites dimensions du boîtier ont fait que je devais enlever le disque dur pour créer de l'espace pour le disque SSD, un Crucial M4. Ça a très bien fonctionné, le temps de démarrage du système et des applications a chuté et la performance était celle attendue d'un ordinateur léger avec un disque rapide : le facteur limitatif était alors le processeur et non plus le disque dur. Cependant, j'ai réussi à faire cela au prix de la perte d'espace disque, puisque le Crucial ne contient que 64 Go. D'autres disques SSD étaient disponibles, mais ils coûtaient plus cher. Bien que les prix aient baissés pendant l'année, les utilisateurs doivent s'attendre à payer environ 1 $US par Go : de gros SSD comportant plus de 500 Go peuvent valoir plus que l'ordinateur lui-même. Si le disque hybride tient ses promesses, je peux peut-être obtenir le meilleur des deux technologies à l'intérieur de l'espace physique limité disponible dans ce petit ordinateur.

I already had a working Xubuntu 14.04 system I was happy with, so I decided to clone the existing setup instead of going through the full installation process. The system detected the new drive - connected through an external USB adapter - as a single unit with no problems. The drive comes completely uninitialized, with no partition table as reported by gparted. My original partitioning consisted of an ext4 boot partition. The rest of the Crucial drive was set up as an LVM physical unit, out of which I had carved a 15 GigaByte logical volume for the system root, and another for /home. There was still some space available for future applications. /dev/sda2 243M 40M 187M 18% /boot /dev/mapper/SSD–VG-System 15G 7,8G 7,1G 49% / /dev/mapper/SSD–VG-Home 20G 5,0G 14G 27% /home After creating an MS-DOS partition table and partitioning the new Toshiba hybrid drive in the same way, I then copied over each partition, installed GRUB on the new unit, and booted the computer from the new drive over USB just to make sure everything was working correctly. I now got up to 901 GigaBytes free for user data - or 850 GB when the standard 5% was reserved for root’s use. /dev/sda1 976M 40M 870M 5% /boot /dev/mapper/SSHD-System 15G 7,8G 7,1G 49% / /dev/mapper/SSHD-Home 901G 5,0G 850G 1% /home

Ayant déjà un système Xubuntu 14.04 qui fonctionnait et qui me plaisait bien, j'ai décidé de cloner le système existant au lieu de faire une nouvelle installation. Le système a détecté sans problème le nouveau disque - connecté via un boîtier USB externe - comme une unité simple. Au départ, le disque n'est pas initialisé et n'a pas de table de partition, selon gparted.

Le partitionnement original comportait une partition boot formatée en ext4. Le reste du disque Crucial était configuré comme une unité physique LVM, dont j'ai créé un volume logique de 15 Go pour la racine du système et un autre pour /home. Il restait encore un peu d'espace pour des applications à venir.

/dev/sda2 243M 40M 187M 18% /boot /dev/mapper/SSD–VG-System 15G 7,8G 7,1G 49% / /dev/mapper/SSD–VG-Home 20G 5,0G 14G 27% /home

Après avoir créé une table MS-DOS de partitions et partitionné le nouveau disque Toshiba hybride de la même façon, j'ai ensuite copié chaque partition, installé GRUB sur l'unité nouvelle et démarré l'ordinateur à partir du nouveau disque (sur USB) pour m'assurer que tout fonctionnait correctement. J'avais maintenant 901 Go d'espace libre - ou 850 Go quand les 5 % standards étaient réservés pour l'utilisation de root.

/dev/sda1 976M 40M 870M 5% /boot /dev/mapper/SSHD-System 15G 7,8G 7,1G 49% / /dev/mapper/SSHD-Home 901G 5,0G 850G 1% /home

I then switched off the computer and got out the old screwdriver to install the hard drive in its place. The hard drive is at the top left of the picture, with the CPU and its cooling fan visible at the top right, RAM slots at bottom right and the WiFi card at bottom left. As you can see, there is little space left over in this computer! Now, for some testing. I compared several typical actions both with the former Crucial SSD and the new hybrid drive. In both cases, the system comes up in 31s - there are no measurable differences. With the new drive, Gimp starts up in 18s, while LibreOffice Writer needs just 5s. These are just about the same times measured with the SSD, and a definite advance over the traditional spinning disk drive this computer came with. Speeds are much higher and the system is much more responsive. In fact, I did not see any user-noticeable differences between the hybrid Toshiba drive and the pure SSD drive - at least, not during everyday tasks.

From a technical standpoint, there are some limits. The hybrid drive has the same SATA-III 6 Gbps interface most SSD drives have today. However, for the time being, no consumer hard drive technologies will fill this bus up completely: laptop platter disks spinning at 5400 rpm are limited in real terms to read speeds in the 100 - 120 MByte/s range, while SSDs may get up to 300-400 MByte/s. As for the hybrid drive, it has been clocked at up to 172 MByte/s read speed (http://hdd.userbenchmark.com/Toshiba-Notebook-SSHD-1TB/Rating/1957&tab=Benchmarks). However, it should be noted that results will depend on whether the data accessed is inside the SSD part, or if it needs to be retrieved from the platter. With this type of cache, we can expect best results from usage patterns that access small amounts of data that fit into the SSD part. If we need to access large amounts of varied data such as in video editing, we could expect much of this data to reside on the slower platter, thus negating the usefulness of the hybrid drive concept. On the other hand, a small, compact, operating system used for Internet access and light office tasks is ideal - and this is just about the projected use of a netbook with Xubuntu. Most system applications and user data fit within the 8 GigaByte cache and are accessed at SSD speeds. Other, larger and less-often accessed data stay within the 1 TeraByte platter and are accessed when necessary, though at a slower pace. All in all, this concept of hybrid drive is probably a very pertinent upgrade for your netbook, though perhaps less so for a tower computer that could fit in an extra SSD as well as the original disk.