raw files are HUGE

"AZ Nomad" <aznomad.2@PremoveOBthisOX.COM> wrote in message news:slrneuu3rc.u5s.aznomad.2@ip70-176-155-130.ph.ph.cox.net
> On Wed, 7 Mar 2007 18:37:35 +0000 (UTC), Dave Martindale <davem@cs.ubc.ca> wrote:
> > AZ Nomad <aznomad.2@PremoveOBthisOX.COM> writes:
>
> > > Pretty much, drive speeds have gone up in step with drive capacities.
> > > You get greater capacity either with more platters or a higher data density.
> > > Both translate to greater throughput given the same rotational speed.
>
> > No, drive speeds go up with about the square root of drive capacity.
> > Capacity increases with higher track density on a platter, more
> > platters, and higher data density along the track. Only the latter

> The number of platters hasn't increased over the years.

It fluctuates.

> The top capacity drives have more platters than entry level drives,

But they didn't use the maximum number of platters possible for a long time.

> but the number of platters used hasn't increased over the last twenty years.

Oh, yes it did.

> You're not going to find a drive with eighty platters.

But you may find them with the maximum number that can fit within a standard
half height drive. But then, with perpendicular recording now, the need for that
may be over for quite a while again.

"Dave Martindale" <davem@cs.ubc.ca> wrote in message news:esn0pf$b84$1@swain.cs.ubc.ca
> AZ Nomad <aznomad.2@PremoveOBthisOX.COM> writes:
>
> > Pretty much, drive speeds have gone up in step with drive capacities.
> > You get greater capacity either with more platters or a higher data density.
> > Both translate to greater throughput given the same rotational speed.
>

> No, drive speeds go up with about the square root of drive capacity.

Platter capacity.

> Capacity increases with higher track density on a platter, more
> platters, and higher data density along the track. Only the latter
> increases data rate given the same rotational speed. The other two
> factors only increase the total number of tracks.
>
> Dave

On Wed, 7 Mar 2007 18:37:35 +0000 (UTC), Dave Martindale <davem@cs.ubc.ca> wrote:


>AZ Nomad <aznomad.2@PremoveOBthisOX.COM> writes:

>>Pretty much, drive speeds have gone up in step with drive capacities.
>>You get greater capacity either with more platters or a higher data density.
>>Both translate to greater throughput given the same rotational speed.

>No, drive speeds go up with about the square root of drive capacity.
>Capacity increases with higher track density on a platter, more
>platters, and higher data density along the track. Only the latter
>increases data rate given the same rotational speed. The other two
>factors only increase the total number of tracks.

You're right about performance going up w/ the square root of capacity...
Think of tracks*data_density*platters as data in three dimensions.
The platters is pretty much fixed; track density and data density have both
improved. Only data density improves performance. You can only
read one track at a time.

On Thu, 08 Mar 2007 04:07:12 GMT, AZ Nomad wrote:

> You're right about performance going up w/ the square root of capacity...
> Think of tracks*data_density*platters as data in three dimensions.
> The platters is pretty much fixed; track density and data density have both
> improved. Only data density improves performance. You can only
> read one track at a time.

One head can only read one track at a time, but I recall reading
about drives that had two or three read/write heads. This might
have been 15 or more years ago, so I don't recall whether the heads
were constrained to the same track, but I don't think so. IIRC,
there were independent actuators. I'm sure that these drives were
out of my price range, nor were they likely to be the MFM and RLL
drives that I used back then.

ASAAR wrote:
> On Thu, 08 Mar 2007 04:07:12 GMT, AZ Nomad wrote:
>
>
>>You're right about performance going up w/ the square root of capacity...
>>Think of tracks*data_density*platters as data in three dimensions.
>>The platters is pretty much fixed; track density and data density have both
>>improved. Only data density improves performance. You can only
>>read one track at a time.
>
>
> One head can only read one track at a time, but I recall reading
> about drives that had two or three read/write heads. This might
> have been 15 or more years ago, so I don't recall whether the heads
> were constrained to the same track, but I don't think so. IIRC,
> there were independent actuators. I'm sure that these drives were
> out of my price range, nor were they likely to be the MFM and RLL
> drives that I used back then.
>

Standard practice is multiple heads per cylinder (one head per surface),
but only one active R/W head at a time, so only one set of R/W channel
electronics is needed.

In the 80's, there was at least one rather expensive HD (ISIS) with parallel
R/W channels, but only one shared actuator. Great for STR, but no help
for seek time.

In the 60's, there was at least one HD (IBM 1301)which offered multiple
actuators, which potentially gave improved STR as well as improved seek time.
But IIRC, the max. seek time on that huge beast was still seven seconds:
the time to recirculate the oil in the hydraulic adder (sometimes needed
to remove oil bubbles).

In the 50's (the dawn of HD time), the IBM 350 had one actuator and two
(IIRC) heads for its 25-platter assembly. For a short seek, the actuator
moved in or out along the radius of the platter stack; for a long seek,
the actuator moved out beyond the platter stack, then up or down parallel
to the central shaft, then in to the desired platter and cylinder. Seek
times were rather long, but still beat the snot out of the competition,
which was mag. tape.
--
Cheers, Bob

On Thu, 08 Mar 2007 06:51:25 -0500, Bob Willard wrote:

>> One head can only read one track at a time, but I recall reading
>> about drives that had two or three read/write heads. This might
>> have been 15 or more years ago, so I don't recall whether the heads
>> were constrained to the same track, but I don't think so. IIRC,
>> there were independent actuators. I'm sure that these drives were
>> out of my price range, nor were they likely to be the MFM and RLL
>> drives that I used back then.
>
> Standard practice is multiple heads per cylinder (one head per surface),
> but only one active R/W head at a time, so only one set of R/W channel
> electronics is needed.

Well of course I've never heard of a drive that didn't have a head
per platter surface. Seek time between surfaces would really suffer
if a disk drive resembled a one head per cylinder carousel. <g>
The ones I heard of with multiple sets of heads probably had only a
single set of R/W channel electronics per stack of heads, but a set
for every stack of heads. Although they could have been completely
independent, I imagine that when the channels were active, they were
all servicing the same track on the same platter surface, buffering
the entire track and of course allowing the complete track to be
read in a fraction of the normal time.

"AZ Nomad" <aznomad.2@PremoveOBthisOX.COM> wrote in message news:slrneuv2vg.8mm.aznomad.2@ip70-176-155-130.ph.ph.cox.net
> On Wed, 7 Mar 2007 18:37:35 +0000 (UTC), Dave Martindale <davem@cs.ubc.ca> wrote:
>
>
> > AZ Nomad <aznomad.2@PremoveOBthisOX.COM> writes:
>
> > > Pretty much, drive speeds have gone up in step with drive capacities.
> > > You get greater capacity either with more platters or a higher data density.
> > > Both translate to greater throughput given the same rotational speed.
>
> > No, drive speeds go up with about the square root of drive capacity.
> > Capacity increases with higher track density on a platter, more
> > platters, and higher data density along the track. Only the latter
> > increases data rate given the same rotational speed. The other two
> > factors only increase the total number of tracks.
>
> You're right about performance going up w/ the square root of capacity...

Platter capacity.

> Think of tracks*data_density*platters as data in three dimensions.

> The platters is pretty much fixed;
> track density and data density have both improved.

> Only data density improves performance.

Right, so much for your:
"You're right about performance going up w/ the square root of capacity"

> You can only read one track at a time.

"Bob Willard" <BobwBSGS@TrashThis.comcast.net> wrote in message
news:huSdnU9mNLskZXLYnZ2dnUVZ_ualnZ2d@comcast.com. ..
> ASAAR wrote:
>> On Thu, 08 Mar 2007 04:07:12 GMT, AZ Nomad wrote:
>>
>>
>>>You're right about performance going up w/ the square root of capacity...
>>>Think of tracks*data_density*platters as data in three dimensions.
>>>The platters is pretty much fixed; track density and data density have both
>>>improved. Only data density improves performance. You can only
>>>read one track at a time.
>>
>>
>> One head can only read one track at a time, but I recall reading
>> about drives that had two or three read/write heads. This might
>> have been 15 or more years ago, so I don't recall whether the heads
>> were constrained to the same track, but I don't think so. IIRC,
>> there were independent actuators. I'm sure that these drives were
>> out of my price range, nor were they likely to be the MFM and RLL
>> drives that I used back then.
>>
>
> Standard practice is multiple heads per cylinder (one head per surface),
> but only one active R/W head at a time, so only one set of R/W channel
> electronics is needed.
>
> In the 80's, there was at least one rather expensive HD (ISIS) with parallel
> R/W channels, but only one shared actuator. Great for STR, but no help
> for seek time.
>
> In the 60's, there was at least one HD (IBM 1301)which offered multiple
> actuators, which potentially gave improved STR as well as improved seek time.
> But IIRC, the max. seek time on that huge beast was still seven seconds:
> the time to recirculate the oil in the hydraulic adder (sometimes needed
> to remove oil bubbles).
>
> In the 50's (the dawn of HD time), the IBM 350 had one actuator and two
> (IIRC) heads for its 25-platter assembly. For a short seek, the actuator
> moved in or out along the radius of the platter stack; for a long seek,
> the actuator moved out beyond the platter stack, then up or down parallel
> to the central shaft, then in to the desired platter and cylinder. Seek
> times were rather long, but still beat the snot out of the competition,
> which was mag. tape.

And the DEC RS09 had fixed heads, one per track, literally.

On Wed, 07 Mar 2007 08:25:01 -0600, chrisv <chrisv@nospam.invalid>
wrote:

>John Turco wrote:
>
>>Hard disks have been around far longer, than flash memory. Hence, it's
>>unrealistic to expect the same kinds of rapid price/performance gains,
>>from such mature technology.
>
>Consider, also, that HD capacity increases are subject to big leaps
>when a new technology is introduced, followed by a plateau until the

Such as the recent change to using vertical magnetic domains instead
of horizontal. I think all the new SATA drives are already using
this.

>next leap. Flash-memory capacity, on the other hand, inexorably
>increases according to Moore's Law.
Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

On 2007-03-03 18:16:40 -0800, "Sameer" <sameerxahuja@gmail.com> said:

>
> I tried winzip and winrar but they cant compress them much. Is there
> anything else which works?

They can't be compressed much. Nikon offers a 'compressed' RAW format
in-camera. I can't tell the difference from the non-compressed one.
They are the same size. Besides, you really don't want to do anything
that might modify an original RAW file.

--
Waddling Eagle
World Famous Flight Instructor