Re: [CAD_CAM_EDM_DRO] Sneakernet

10Gb's! Well that sure would make my weekends at lot more fun, I'm just
waiting for the engineers to arrive for my T3 right now. I've had to buy the
house next door to have to beauty plumped in though. On a more serious note
I've seen my 100mb cards take up to 14 or so minutes sending 700 - 800mb!
Even to a simpleton like me... that is not 100mb/s. I've had them going to
30 or 40 minutes SOLID with no disk acess other than the files going across.
Both PC's have 128+, one has 256, and lots of spare disk space. Both the
cards are most definitly 100mb but silly old me snapped the network
connector when I stood up with the laptop! If I've ever seen an ultimately
pointless conenctor in my life it had to have been this one. It needs
pushing down now to get it to even show a connection. (Note to himself: Try
extra cup for 100mb/s, if not sucessful, move onto rolls of solder). I think
two of the pins might be shorted but the only response I get from Dynalink
(Now franchised) is 'Try our store in the UK', and then they should go on
'Who will be happy to inform you they do not stock this item anymore and
that you should consult a foreign franchise of Dynalink, possibly us.

Enough complaining,
John

----- Original Message -----
From: "Tony Jeffree" <tony@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Thursday, April 05, 2001 9:54 AM
Subject: Re: [CAD_CAM_EDM_DRO] Sneakernet


> At 20:27 04/04/2001 +0000, you wrote:
> > > Actually, with a few DAT tapes in your pocket, you can achieve MUCH
higher
> > > data transfer rates with sneakernet than with 100 Mbit/s Ethernet.
> >
> >Absolute baloney! I have only 10 MB/S ethernet, and I can transmit
> >the full EMC ditribution set in less than 5 seconds. So, that is close
to
> >1 MBYTE / second. Given the time to write a tape, carry it, and read
> >it at the other location, I'm sure that even the 10MB/sec ethernet is
> >a little faster. The 100 MB/sec is WAY faster, it should transfer at
> >nearly 100% of the transfer rate of the slowest hard disk drive.
> >Note that with the net, you are reading from one computer and writing
> >on the other SIMULTANEOUSLY.
>
> Very far from being absolute baloney, actually. The point is that when
you
> are talking about transferring very large volumes of data, the speed of
the
> network becomes less important relative to the speed of accessing it
> from/writing it to backing storage devices, and even the speed at which
you
> can transfer data between the network interface and the computer's RAM can
> become a major limiting factor.
>
> If you are shipping a significant amount of data (i.e., more than you can
> accommodate in RAM on the source or destination machines - lets say more
> than 100 megabytes, for the sake of argument - not unreasonable for a
> well-specced PC with 256 megs of RAM - you gotta leave some room for
> Windoze <G>), then the data transfer rate between the two machines is
> absolutely limited by the rate at which you can get the data off the
source
> machine's backing storage (which we will assume is the same rate at which
> the target machine can write to its backing storage). However fast the
> network is, once you've shipped the first 100 megs, you're down to the
> speed of the disk/floppy/tape etc. accesses - the data has to be
somewhere,
> and it ain't in RAM.
>
> Given that the stuff must already be available on a disk (or cartridge,
> tape, floppy...etc), in the source machine, it can indeed be quicker to
> simply unplug the disk (or cartridge, tape, floppy...etc) from the source
> machine & plug it into the destination machine. That way, the data is
> immediately available to the target machine, without the delays imposed by
> reading, transferring across the net and writing.
>
> Its not unusual to have removable hard drives on computers these days - I
> have 2Gigabyte Jazz drives on my machines, for example. Using your 10
> Mbit/S Ethernet network, and your transfer rate of a megabyte/second
(which
> is close to the maximum you can achieve on 10 Mbit/s Ethernet), it would
> take me 2000 seconds - a little over half an hour - to transfer the
> contents of one Jazz cartridge over the LAN. Even with 100 Mbit/s
Ethernet
> (which I have on my home/workshop LAN), and assuming that a Windows
machine
> can actually use the full 100 Mbit/s available on a continuous basis,
while
> simultaneously doing bulk disk accesses (which I seriously doubt, by the
> way), and ignoring the access speed of the Jazz drive (a relatively slow
> hard drive), we're talking 3 minutes to ship the contents of a 2 Gig Jazz
> cartridge from machine to machine on my network. I absolutely guarantee
> that I can unplug the cartridge, walk to any other machine on my network,
> and plug the cartridge in in less than 3 minutes. 30 seconds tops.
>
> With removable hard drives (or DAT tapes, as in my original comment) of,
> say, 40 Gigabytes capacity, the data transfer rates you can achieve with
> sneakernet become really quite high - equivalent to a data rate of 640
> gigabits per second if you can unplug/replug the drive or tape within 30
> seconds. Even the leading edge LAN technologies only manage 10
> Gigabits/second right now.
>
> Regards,
> Tony
>
>
>
>
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