Please create an account to participate in the Slashdot moderation system

 



Forgot your password?
typodupeerror

Comment: Charge trap vs floating gate NAND... (Score 4, Interesting) 184

by AcquaCow (#49658379) Attached to: Enterprise SSDs, Powered Off, Potentially Lose Data In a Week

Newer 3D NAND is using a charge trap design which basically solves the electron leakage issue found with the older floating gate NAND...

Also, the move to the newer 3D NAND brings us back up to 40nm processes vs the 10nm gates we are currently working with, allowing for much better reliability.

Disclaimer: I've been selling enterprise flash storage for the last 6 years.

Comment: Re:that can't be true (Score 1) 162

by AcquaCow (#49521295) Attached to: New PCIe SSDs Load Games, Apps As Fast As Old SATA Drives

You can't read game files faster because the process that reads the game file is single threaded vs multi-threaded... so it can only read as fast as a single thread can read.

A fully saturated CPU has enough lanes to do about 26-28GB/sec, but a single I/O thread might only be able to do 100-200MB/sec.

There was never any reason in the OS before today to make that any faster because the spinning disks that fed data to the CPUs couldn't do more than 100MB/sec.

Now that we have all this great flash, code needs to be re-written to be able to use other idle CPU time to spin up more threads and read the data faster.

Comment: Re:ISTR hearing something about that... (Score 1) 162

by AcquaCow (#49521207) Attached to: New PCIe SSDs Load Games, Apps As Fast As Old SATA Drives

It's worth remembering that 98k IOPS will be at a very small block size and will rapidly drop as you increase block size to 4K-1MB as the larger transfer size will directly equate to less I/O.

The real problem is that apps are not written for multi-threaded I/O which is what you really need in order to take advantage of the throughput provided by PCI-e flash.

Comment: Re:It all depends on the workload... (Score 1) 162

by AcquaCow (#49521181) Attached to: New PCIe SSDs Load Games, Apps As Fast As Old SATA Drives

Booting from RAID is more supported, and the support is baked into nearly every BIOS out there... booting PCI-e over NVMe or UEFI is brand new and very few things support it and all the code is new.

Booting through a raid card that has it's own BIOS is nothing like booting off of a native PCI-e device.

Comment: Re:"old sata drives"? (Score 1) 162

by AcquaCow (#49521127) Attached to: New PCIe SSDs Load Games, Apps As Fast As Old SATA Drives

The PCI-e native SSDs are indeed faster, the problem is, the code reading data off of them (your application/os) isn't written to take advantage of the increased speeds. Single threaded reads cap out at the read speed of a single thread, and that isn't that fast. This is especially true if they are 4K reads vs 1M reads, as you aren't going to saturate anything until you get up into larger read sizes.

To really take advantage of the bandwidth SSDs enable, you need to be running multiple parallel apps running multiple reads, or you need an app that can do multi-threaded reads.

Comment: Re:SSDs (Score 2) 162

by AcquaCow (#49521103) Attached to: New PCIe SSDs Load Games, Apps As Fast As Old SATA Drives

This is because you get stuck leaving the CPU to handle all the context switching between virtual block storage in DRAM and memory. The CPU has to copy data out of block and into memory before it can actually use it, so by making a ram disk you end up giving the CPU 2-4x the amount of work to do for what should be a DMA read/write, which would normally be offloaded.

Also, your reads from your game are going to be single-threaded, and a single read/write thread is going to be pretty slow.

Comment: Re:We don't need density! We need longer life! (Score 1) 42

by AcquaCow (#49361085) Attached to: Toshiba Announces 3D Flash With 48 Layers

There's no reason to use SLC these days really... Once you start writing in large density with intent on retaining data for some period of time, you'll be striping that data across 10-100 SSDs... The combined wear-life even with cheaper MLC drives still puts you up over 100 years for most products.

It's pretty easy to take the Drive Writes Per Day (DWPD) or PetaBytes Written (PBW) for the drives and add them all up... most any install will 10+ drives will outlast any standard 5 year hardware refresh cycle.

Disclaimer: I work for a large flash company and have been selling this stuff for the last 5 years.

-- Dave

Comment: The problem with this article... (Score 1) 68

...is that in a properly-designed SSD, there is no such thing as data fragmentation. You lay out the nand as a circular log and write to every bit of it once before you overwrite, and maintain a set of pointers that translates LBA to memory addresses.

Pretty much every SSD vendor out there has figured this out a few years ago.

Comment: Digital scans in a safe deposit box (Score 1) 245

by AcquaCow (#46882357) Attached to: Ask Slashdot: How To Back Up Physical Data?

I have a PDF scan of all important IDs/health cards/etc on a drive in my safe deposit box. It's also where I store my long term email/document archives.

I keep a mirror at home, which is what I update most frequently and any time I go to the bank, I just swap the external home drive with the one in the safe deposit box, go home and rsync the current data to it.

My safe deposit box key lives in a floor safe in my home which should survive even a gas leak explosion/tornado/etc.

-- Dave

"I prefer rogues to imbeciles, because they sometimes take a rest." -- Alexandre Dumas (fils)

Working...