Re: usb flash drives / sd
On Sun, Aug 13, 2017 at 09:58:58AM -0400, Fungi4All wrote:
> > From: dsr@randomstring.org
> > To: Doug <dmcgarrett@optonline.net>
> > jumpy@tutanota.com, debian-user@lists.debian.org
> >
> > On Fri, Aug 11, 2017 at 06:58:47PM -0500, Doug wrote:
> >>
> >> On 08/11/2017 05:11 PM, Dan Ritter wrote:
> >> > On Fri, Aug 11, 2017 at 02:25:01PM -0500, Doug wrote:
> >> > > On 08/11/2017 01:46 PM, jumpy@tutanota.com wrote:
> >> > > > There are three major types of flash chip types : SLC - MLC - TLC
> >> > > >
> >> > > > how-to check my usbkey/sd/memory card ?
> >> > > >
> >> > > > --
> >> > > > Securely sent with Tutanota.
> >> > > I am not being a wiseguy.
> >> > > What is the difference, and why does it matter?
> >> > The basic difference is the number of bits recorded in a single
> >> > cell, and that affects both the storage density and its
> >> > long term reliability.
> >> >
> >> > More bits == more dense but less reliable.
> >> >
> >> > To compensate for long term reliability, SSD manufacturers use
> >> > a variety of strategies involving staging data in RAM,
> >> > compressing it, and implementing other special storage
> >> > structures.
> >> >
> >> > On a removable-media flash device, none of those strategies
> >> > are used.
> >> >
> >> > -dsr-
> >> >
> >> Perhaps I misunderstood. I thought you were referring to usb flash drives.
> >> Do you mean these little chip gizmos that go into digital cameras?
> >>
> >> (Hope I am not being a nuisance.)
> >
> > What"s the difference between:
> >
> > - a USB "thumb drive"
> > - a USB SSD
> > - an SD, SDHC, SDXC "memory card"
> > - a SATA SSD
> > - an M.2 SSD
> >
> > They are all persistent data storage (i.e. doesn"t disappear
> > when the power goes off) using a technology that stores
> > electrons (or lack of electrons) in "cells". They differ in:
> >
> > - interface to your computer
> > - strategies for reliability
> > - speed and capacity
> > - quality control
> > - price
>
> My earlier suspicion that when I see an 8gb, a 16gb, a 32gb, and a 64gb on the rack looking the same
> but stamped differently is most likely the same exact chip/s programmed for density and reliability.
Generally this is not the case.
Different speeds, however, are often the result of testing and
sorting at the factory. And a warranty is a pure business
decision, influenced by technology but not dependent on it.
> Hence in a model as the above you chose the least capacity for maximun reliability. It is very common
> in the computer industry to manufacture one single piece of hardware and alter firmware and packaging
> to meet different market groups. It is always cheaper than manufacturing 4 different things.
> I also think processors are about the same, they program the speed down for having cheaper, cooler,
> less energy consuming, versions of the same superfast processor that gamers will pay double for.
This is certainly true.
For example, the entire new line of AMD "Zen" CPUs, from 4 cores
up through 32, are the same 8 core chips on the same process.
They are tested, graded, and sorted, then combined with other
chips into a multi-chip module.
The result is a line of desktop and server CPUs that all have
the same feature set, and only differ in terms of speed and
number of working cores:
4, 6, 8, 12, 16 cores on the desktop;
8, 16, 24, 32 cores on servers, plus interconnects for 2
sockets.
Four different plugs (single chip, double chip, and quad chip
single socket, quad chip double socket for servers).
When they fix problems for one of them, they get to fix the same
problem on all the others for free.
-dsr-
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