Ultimate pocket gadget: Iphone, Windows Mobile, or Nokia Tablet

Apple has released its 3G versions of Iphone: you probably are already tired of hearing this word, iphone. But yes, I believe this is the one. Oh gee, why only apple makes things right?

OK, I have owned a blackberry, Nokia internet tablet, ATT 8525 Windows Mobile, but I still want an iphone. Here's the story.

What do you want to do with a pocket electronic gadget?
1) communication: to make phone calls, internet chat, messaging, email
2) basic internet surfing, such as checking news headline, weather, traffic, googling
3) maps, GPS is a plus
4) multimedia, such as watching videos,listening to music
5) personal organizer, such as addressbook, calendre, to-do list
6) gaming
7) E-book reader

Let one first review all these products.

1) Blackberry: The advantages of blackberry phones are push-emails and full-qwerty keyboard. But these features have been and will be included in other phones. It allows third-party applications in Java. Unless there is a big development in Symbian OS, I doubt that blackberry phones won't be able to compete with iphone, windows mobile phones in high-end applications for pocket computers. However, blackberry indeed has decent phones, very clear voice and very helpful voice command features. It will remain a good choice for cellular phones with message support. 

2) Windows mobile. I used a Cingular 8525(HTC Hermes). I don't like this bulky phone. Maybe Samsung's models are better. Well, this is Microsoft's Windows. So, almost all feature can be implemented. At the same time, like Windows VS MacOS,  or Zune VS IPOD, don't expect everything to work perfectly. I especially don't like the fact that almost any usable programs in windows mobile is not free. 

3) Nokia internet tablet. I owe a Nokia 770. There are great improvements along this product line to include camera, GPS, Qwerty-keyboard. Big thing, it is a Linux computer! So, you can have all the wonderful and free programs running in Linux. I indeed enjoyed the touchscreen, and a bigger screen( good enough to read ebooks and pdf files).  But this is not a cellular phone (although you can use the phone feature through internet, such as skype, google talk, gizmoproject). I believe Linux in the long run has advantages over Symbian. Nokia, a big fan for Symbian has converted their top intelligent phones to Linux.   

4) Google has created all nice web applications for mobile internet devices. All it need is a platform. It's no surprise that Google will introduce it's own Cellular phone version. Anyway, when you can have Wireless Internet connections everywhere, who will need a cellular phone? 

5) Iphone, almost perfect! While applications are important, they are not all. Imagine there are so many MP3 players in the market, why does IPOD win the major share? I am a big fan for MacOS due to its simple operation and a lot of free applications. MacOS is indeed a powerful Linux + a nice Windows user interface. 

My perfect pocket PC will be

1) having a decent computer system, such as CPU, memory, flash-card support. 

2) running Linux or MacOS, with lots of free application available.

3) big LCD screen while foldable to fit in my pockets. 

4) support external devices, such as printer, monitor, keyboard via USB, bluetooth, ...

5) good touchscreen features, handwriting recognition. I love Apple's two-finger control. Hey, most people has ten fingers, and a mouth, and body movements. Can we use some of these too?

Connecting SATA disk array

Let's say, you want an external enclosure for sata drvies and hook up to your computer. Here's the solution.

1) use sata multilane: check this guide. Basically, you can connect four sata drives to four sata ports in your computer with a single sata multilane cable(bridge).

2) use sata port multiplier, check this guide Theoretically, it is possible to hook up 15 sata drives to one sata port on your computer(motherboard or PCI sata adaptor) with port multiplier. Yet, they have to share 3Gbps band width. Actually, commercial SATA disk arrays use port multiplier. Check addnonics as an example: it has internal/external 5x1 port multiplier which allows 5 sata drives on one sata/eSATA port.

3) commercial enclosures can also provide interfaces such as Fiber Channel, SCSI, SAS and Infiniband. Check out some commercial products, such as Sans Digital.

FAQ:
1) how to get an eSATA port?
You can use a SATA to eSATA converter or get an eSATA PCI adaptor.

Disk storage solutions for workstations

In this article, I discuss the options for installing storages (hard disks) on workstations and servers.

Let me first explain some of the terminologies

1) the type of physical hard disks
Desktops and workstations usually use 3.5in hard disks, which come in the following interfaces:

• a) Ultra-ATA(parallel Advanced Technology Attachment, also known as IDE or EIDE) drives. Ultra-ATA 100 supports the transfer rate of 100M/s and has the capacity as large as 750GB for a single drive. These are used in old desktops, and have been replaced by SATA drives for better performance. Price: 750G for $120.
• b) SATA(serial-ATA) drives. Currently, SATA-II(or SATA-300) supports a transfer rate of 300M/s (raw bandwidth 3G/s) and the capacity as large as 1TB (Seagate will release a 1.5TB drive soon). Price: 1TB for $200.
• c) SCSI(Small Computer System Interface) drives. Most commonly ones found on market is Ultra-320 (supports 320M/s) and 300GB in capacity. Price: 300GB for $200.
• d) Fiber-channel drives. Common ones on market are FC-AL (Arbitrated Loop) 2G/s (200M/s transfer rate), 300GB for $585.
• e) SAS (Serial Attached SCSI), current 3Gbps models support transfer rate of 375M/s. Price 300GB for $188.
• f) Infiniband, this is relatively new and rare and extremely expensive.

2) Connection type

• a) external or internal: usually the desktop computers and workstations have limited space inside the main case, limited power connectors, motherboard connectors which limit the number of hard drives put inside. For instance, for normal desktops, 4 sata drives are usually at its maximum. Supermicro workstations can put 8 drives inside. So, if you want bigger storage, an external disk array (including rackmount) is recommended. If we choose an external array, all you need is a (external) connection port from the main workstation/server. You then need a PCI adaptor if the motherboard doesn't come with one.
• b) connection bus. Besides the type of drives mentioned above, we can also connect the external drives with FireWire or USB. The number of drives and the connection speed is summarized in wikipedia, and is copied here:
  

Name	Raw bandwidth (Mbit/s)	Transfer speed (MB/s)	Max. cable length (m)	Power provided	Devices per Channel
SAS	3000	375	8	No	4
eSATA	3000	300	2 with eSATA HBA (1 with passive adapter)	No [11]	1 (15 with port multiplier)
SATA 300	3000	300	1	No	1 (15 with port multiplier)
SATA 150	1500	150	1	No	1 per line
PATA 133	1064	133	0.46 (18 inches)	No	2
FireWire 3200	3144	393	100; alternate cables available for 100 m+	15 W, 12–25 V	63 (with hub)
FireWire 800	786	98.25	100[12]	15 W, 12–25 V	63 (with hub)
FireWire 400	393	49.13	4.5[12][13]	15 W, 12–25 V	63 (with hub)
USB 2.0	480	60	5[14]	2.5 W, 5 V	127 (with hub)
Ultra-320 SCSI	2560	320	12	No	16 (HBA is a device)
Fibre Channel over copper cable	4000	400	12	No	126 (16777216 with switches)
Fibre Channel over fiber	10520	2000	2–50000	No	126 (16777216 with switches)
Infiniband 12X Quad-rate	120000	12000	5 (copper)[15][16] <10000>	No	1 with Point to point Many with switched fabric

OK, we can decide what kind of storage system is good for us. Infiniband, Fiber-Channel, SAS are relatively new and expensive. The common solutions currently are either SCSI or SATA. SCSI has been tested for more than 20 years for its reliability and availability. Many businesses still prefer SCSI for mission critical appliations. SATA drives are relatively new. But due to its price and performance, it has gained more commercial market. In another aspect, external SATA 3.0Gbps drives may be connected to SAS backplanes, or Firewire, Infiniband buses.

I will prefer SATA drives because 1) it's big (1TB each drive); 2) it's cheap; 3) the flexibility of connections. I will focus on SATA drives below.

If you want to put SATA drives inside the workstation, notice that normal motherboard only supports 4-6 SATA ports, you will need another SATA adaptor or port multiplier(can also mounted as a PCI card). Also, there are limited SATA power connectors. You can buy IDE to SATA power connector with splitters(usually a few dollars). But make sure that you have a big power supply.

For external drives, there are commercial disk arrays which comes with either eSATA, ethernet, SAS, Firewire, USB interfaces. If speed is not the first priority, for instance, backup devices, you can take Firewire, USB, or ethernet interfaces. Otherwise, you want these external drives run as fast as internal drives, choose eSATA or SAS.

I will discuss how to connect SATA arrays in next blog.