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Would it be as fast as an internal SSD? Would the USB interface slow it down?
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Nish Nishant wrote: Would it be as fast as an internal SSD?
Like many question, the answer is 42 it depends. most internal SSDs use eSATA and external SSDs use USB, but not all interfaces are created equal. For starters there is a difference between USB2 and USB3 throughputs. In many cases USB3 (external) will be faster than eSATA ( assuming head-to-head comparison ), but USB3 will be dependent on how may other devices are connected.
In general, for low - mid data access you won't see much difference between internal and external SSDs but for heavy data access internal has slight advantage.
These sources are bit outdated, but the point is still valid http://www.pcmag.com/article2/0,2817,2413310,00.asp[^] and http://www.itworld.com/article/2693284/usb-3-0-vs-esata-is-faster-better.html[^]
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I'm pretty sure that very few internal SSDs use e(xternal)SATA. As for USB3, it still uses 8/10bit encoding; meaning that 5 gigabits/sec translates to 500MB/sec max. Good SATA SSDs will send data faster than that in sequential reads. USB 3.1's speed doubling could push an external drive over the top; but only if it's a PCIe model internally.
Did you ever see history portrayed as an old man with a wise brow and pulseless heart, waging all things in the balance of reason?
Is not rather the genius of history like an eternal, imploring maiden, full of fire, with a burning heart and flaming soul, humanly warm and humanly beautiful?
--Zachris Topelius
Training a telescope on one’s own belly button will only reveal lint. You like that? You go right on staring at it. I prefer looking at galaxies.
-- Sarah Hoyt
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USB3 is theoretically in the same speed class as sata, so it could be as fast as an internal (non-PCIe) SSD; with 3.1 being comparable to 2 PCIe 2.0 lanes. In practice, even devices marketed as USB SSDs generally are 4 flash chip models (laptop or budget desktop equivalent) not 8 chips like higher end desktop SSDs and fall short of high end models. Ones marketed as just high capacity flash drives generally have only 1 flash chip and a crappy controller and are much slower. Cheap USB3 flash drives use bottom binned flash and crappier controllers and make the former look good. USB2 is slow enough that all flash drives will suck similarly.
Did you ever see history portrayed as an old man with a wise brow and pulseless heart, waging all things in the balance of reason?
Is not rather the genius of history like an eternal, imploring maiden, full of fire, with a burning heart and flaming soul, humanly warm and humanly beautiful?
--Zachris Topelius
Training a telescope on one’s own belly button will only reveal lint. You like that? You go right on staring at it. I prefer looking at galaxies.
-- Sarah Hoyt
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What's the advantage to having more flash chips, aside from perhaps higher capacity?
The difficult we do right away...
...the impossible takes slightly longer.
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Parallelism. Reading from/writing to 8 chips can be twice as fast as 4, although normally a bit less in practice because especially for reads you rarely get the data equally spread out over all the chips and on sata devices sequential IO is bottlenecked by the bus. 4 vs 2 or 1 is more dramatic because even easy cases can end up not saturating the bus before maxing the flash out.
(If you want to go deeper into the weeds, for a lot of things its the number of flash dies that really count not the number of chips, and 8x8 die chips will perform similarly to 4x16 die ones. This is a big part of why small capacity SSDs are slower than larger ones: as the individual flash dies get denser the bottom end doesn't have enough to keep up with what the controller is capable of. Generally this is only a significant factor with the lowest size drive in a lineup, with the middle and upper ones performing similarly. The SSD makers seem to've learned their lesson when a round of die shrinks meant that 128GB SSDs were feeling the too few die bottleneck, while 64GB ones were performing awfully.)
Did you ever see history portrayed as an old man with a wise brow and pulseless heart, waging all things in the balance of reason?
Is not rather the genius of history like an eternal, imploring maiden, full of fire, with a burning heart and flaming soul, humanly warm and humanly beautiful?
--Zachris Topelius
Training a telescope on one’s own belly button will only reveal lint. You like that? You go right on staring at it. I prefer looking at galaxies.
-- Sarah Hoyt
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Thanks, Dan. 
The difficult we do right away...
...the impossible takes slightly longer.
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Kinda like RAID-0 for flash chips I guess.
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I have a few Dell Precision M6600s with DUAL SSDs, internal.
I have a USB3/eSATA External Device (BlacX) that I use for Cloning drives.
I can tell you that eSATA out performs the USB3 consistently enough that I use it.
Probably 10% faster.
With USB2, I would put destination and source INSIDE the machine, because it was so much faster for both devices to be on the SATA bus.
Finally, if you are running SSDs, please check for firmware updates! We had a Crucial drive failing because we logged more than 5,000hrs on it, and they had some bad code in the firmware.
I even put a spare SSD in my TiVo to see how the continuous writing is handled. 2yrs, still going, but I am ready to take it out and clone it for safety
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Kirk 10389821 wrote: I even put a spare SSD in my TiVo to see how the continuous writing is handled. 2yrs, still going, but I am ready to take it out and clone it for safety
Check the smart levels if you're concerned; but consumer SSDs are still generally good for a write/day for several years even though the warranty max TB written number is much lower (mainly to pressure enterprise customers to buy higher margin products).
Did you ever see history portrayed as an old man with a wise brow and pulseless heart, waging all things in the balance of reason?
Is not rather the genius of history like an eternal, imploring maiden, full of fire, with a burning heart and flaming soul, humanly warm and humanly beautiful?
--Zachris Topelius
Training a telescope on one’s own belly button will only reveal lint. You like that? You go right on staring at it. I prefer looking at galaxies.
-- Sarah Hoyt
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Nish Nishant wrote: Would it be as fast as an internal SSD?
The laptop comes with a couple USB 3 ports, which is what it's plugged into. I haven't done any speed tests, but it hums along (well, given that it's silent, it doesn't really hum) quite nicely.
Marc
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At work 1,2 and a phone headset.
At home mouse, trackball, two printers, jump drive, powered USB expansion ports
Mongo: Mongo only pawn... in game of life.
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Kind of minimalist compared to your current setup.
work: keyboard, mouse, iphone, usb license dongle
home PC: keyboard, mouse, sdhc card reader.
home Mac: extenal backup HD, iphone (xor kindle).
I'd rather be phishing!
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At work:
0) Keyboard
1) Left handed mouse (for my use)
2) Right handed mouse (for anyone else)
3) USB Plasma globe
4) Monitor USB hub - to give me a few easily accessible ports for when I need them. At times I've had mobile devices and firmware programmers plugged to these.
At home, drop the 2nd mouse and add multiple USB data/charging cables, a printer, an UPS, and probably at least a few cables that don't have anything plugged into the other end. Snarled cluster-elephant doesn't begin to describe my cabling mess at home and nothing this side of a move will (temporarily) fix it; although in the medium term if all of my networking gear goes to 12V USB power I could buy a single 50-100W charging dock and power my modem, router, switch, and (normal) USB hub all off of a single power cord reducing the snarl and outlet congestion somewhat.
Did you ever see history portrayed as an old man with a wise brow and pulseless heart, waging all things in the balance of reason?
Is not rather the genius of history like an eternal, imploring maiden, full of fire, with a burning heart and flaming soul, humanly warm and humanly beautiful?
--Zachris Topelius
Training a telescope on one’s own belly button will only reveal lint. You like that? You go right on staring at it. I prefer looking at galaxies.
-- Sarah Hoyt
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Marc Clifton wrote: (writing ATM software)
Hey Marc ol' buddy ol' pal... you, uh, mind writing me a backdoor into that by chance?
Jeremy Falcon
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Since my PC is an Intel NUC, I've got practically everything running off of USB instead of the usual connectors. It's got exactly one USB port in use, and it's going to a Plugable UD-3000 USB hub, which provides an additional VGA port, Ethernet, audio and a bunch of additional USB3 connectors, one of which is going back to another hub.
The following are all hooked up via USB:
- Keyboard
- Mouse
- SoundBlaster X-Fi (5.1 audio)
- Two monitors
- External SATA/USB hard drive adapter (the toaster kind where you just pop in a drive, not an enclosure)
- DVD burner
- Web cam (which fell somewhere behind my monitor eons ago but is still plugged in)
- MicroSD reader
- One or two extra cables for recharging devices
- Zune (seriously, this thing won't die and I listen to podcasts on it daily)
The printers (one color / one B&W), scanner and UPS are all hooked up to other computers so I don't suppose they count.
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dandy72 wrote: Plugable UD-3000 USB
Ooh, I'm going to have to take a look at that.
Marc
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It's what turned my first-gen Surface Pro into a full-blown workstation, and is now doing the same with my Intel NUC.
(the only reason I've moved away from the Surface Pro is that the NUC can output 4K)
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Marc Clifton wrote:
- credit card reader
- ID scanner
- Verifone pinpa
I'm surprised the spam filter didn't jump to conclusions on this one...
cheers
Chris Maunder
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I'm surprised you don't consider yourself safe enough to put on the 'safe list' I keep hearing about.
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I just don't trust myself. It's those shifty eyes. I'm sure I'm hiding something.
cheers
Chris Maunder
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At work: Let's start out with the ten Bluetooth Smart dongles... Yeah, we develop them, and the software to mesh them up in a network. The protocol sniffer for testing and a Bluetooth master, of course. Mouse and keyboard and headphones and Skype speaker and portable disk. And the wireless charger.
That's the fixed stuff. All the time there is a need for plugging in signal analyzers and temperature sensors and that kind of stuff. FPGA boards. Sometimes, we need USB-to-RS232 adapters to interface to lab equipment lacking USB interface. If the two 10-way hubs get full (not too often, though), there are usually a couple extra sockets left in the PC.
At home it is more limited. Keyboard, mouse, webcam and headphones, printer and flatbed scanner, of course. Usually two portable disks. A multistandard card reader, a numeric keypad, a thermometer, an ISDN adapter, three Arduino cards, a software license dongle and a MIDI cable to my old style keyboard (which only has archaic 5-pin DIN connectors). A transmitter for old-style infrared remote control. Temporary connections for cellphone charging, for my two still photo cameras and video camera. Every now and then someone comes with a floppy disk, so I have to plug in that USB floppy unit. I also have an SATA-to-USB adapter that comes in handy when someone has trouble with their disks and wants me to look at it. I actually have an external CD-reader I use now and then to play my single(!) multichannel audio DTS CD - I haven't found a way to read it through my PC software, but I can hook up a digital cable from the "raw" output of the external CD player, directly to my amplifier, and it will play it, while the player is controlled by the PC (even if it cannot reproduce the sound).
... Are there really that many cables behind my PC, without me worrying about it? Well, blame it on cables being orderly fixed to the wall where appropriate, and proper use of hubs to move the cable mess away from the main box. Actually, the USB usage is more varied at home than at work, even though the total count may be higher at work.
I've never been even close to the USB limit of 128 units on a single hub (or rather: tree), though, neither at work nor at home. We did have some issues at work with the optical fiber USB units; the firmware in those switches were limited to 13 units (and remember that the hubs also count as a unit), so running ten Bluetooth slaves and a master left no room for other USB functions. For new setups, we have different solution without that limitation.
I am still waiting for Thunderbolt hubs in a price range comparable to USB hubs - or, to be realistic: Within one magnitude of USB hubs. Until that becomes a reality, Thunderbolt is not practically usable. With it, I'd throw out USB any day. Obviously that is 'as soon as equipment becomes available with TB interface'. But that won't happen until the egg is laid, or, hubs are available.
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