The picture at Lindows.com looks like its PS doctored from the DocuNote picture.
Note:
1) exact same perspective view
2) exact same pen placement & orientation
3) image of Lindows desktop is NOT trapezoidal like the LCD bezel !!!
No surprise
In my last 5 years I regularly worked on the servo controller block of a drive controller ASIC so I'd like to point out some much under appreciated issues and correct some recurring miss understandings: a) the servo system, b) the real benefit of fluid bearings, c) error correction, d) why an unused surface, e) spin speed
Some short answers are: b) Worn ball bearings seriously disturbs the servo system from keeping the read head or the write head on true center of data track. This puts a ceiling on increasing track densities. c) Very strong error correcting codes are applied to every data block (about 512 bytes) and not on any unused surface. d) As for unused surfaces, there are multiple issues in this decision, but a new feature from some manufacturers is to reserve one outside surface for a template servo pattern & BIOS code so that the drive can self write its own servo patterning and more cheaply load its BIOS code. This reduces / obviates the many hours it takes of very expensive capital equipment to write servo patterns to drives. e) Spin speeds above 10K introduce horrendous resonances at the outside of platters that make servoing tracks much harder. One remedy has been to reduce platter diameter & capacity (by about 10% as I recall).
And the long version of a) & b) or 101 of disk drive servoing: For atleast a decade, hard drives have used embedded servo patterns on every surface that are intermingled with the data areas. Using a dedicated surface for servo worked long ago only because track & data bit densities were much lower. Todays drives typically have 120 or more curved radial servo wedges that costs 5-7% of the surface area. User data tracks nestle between these servo wedges. 1) In these short servo wedge areas, servo tracks contain a few tiny fields of digital servo data followed by several analog modulations so that the servo processor can sense its fractional position within any servo track. Servo tracks actually abutt each other and the only bit change between adjacent servo tracks is in the Gray coded track no. Since IBM patented this many years ago (1980's ?), manufacturers have since added proprietry extra small digital fields to correct for read errors in the digital fields & analog modulations to continuously improve servo tracking and hense improve data track densities. 2) The user data tracks are not neccessarily pitched to be inlign with servo tracks and may be reduced to 2/3 the density of servo tracks. This provides guard space and reduces inter track symbol interference. As the disk spins from servo wedge area on into user data area, it becomes an increasing act of faith that the read head or the write head is indeed still following a track center until we reach the next servo wedge. Such miss tracking is called runout. A major source for Non-Repeatable Runout comes from worn bearings which introduces random wobbling, and this degrades the servoing and limits tracks densities.
Fluid bearings improve upon ball bearings because they don't introduce this NRR so spinning is quiter but more importantly track densities can keep climbing. There are quite a few other NRR & RR terms impacting on servo tracking.
Intelligent life would be dotted in time (throughout billions of years) as much as in space. Even long surviving species would be miniscule relative to the 10 plus ?? billion years of the galaxy. Even if such lucky planets have multiple extinctions and can repeat the occurance of intelligent life, the odds improve only a bit.
What percentage of all such intelligent life is around right now in our blink of time ?.
If our window of observational and communication interest is say some 5 thousand years, then out of a snapshot of 5 billion years of cosmic life, we've reduced the likelyhood of current intelligent life elsewhere in our galaxy by a million or so (give or take a zero).
Time is as much a distance as space.
Slashdot Mirror
The picture at Lindows.com looks like its PS doctored from the DocuNote picture. Note: 1) exact same perspective view 2) exact same pen placement & orientation 3) image of Lindows desktop is NOT trapezoidal like the LCD bezel !!! No surprise
In my last 5 years I regularly worked on the servo controller block of a drive controller ASIC so I'd like to point out some much under appreciated issues and correct some recurring miss understandings: a) the servo system, b) the real benefit of fluid bearings, c) error correction, d) why an unused surface, e) spin speed
Some short answers are:
b) Worn ball bearings seriously disturbs the servo system from keeping the read head or the write head on true center of data track. This puts a ceiling on increasing track densities.
c) Very strong error correcting codes are applied to every data block (about 512 bytes) and not on any unused surface.
d) As for unused surfaces, there are multiple issues in this decision, but a new feature from some manufacturers is to reserve one outside surface for a template servo pattern & BIOS code so that the drive can self write its own servo patterning and more cheaply load its BIOS code. This reduces / obviates the many hours it takes of very expensive capital equipment to write servo patterns to drives.
e) Spin speeds above 10K introduce horrendous resonances at the outside of platters that make servoing tracks much harder. One remedy has been to reduce platter diameter & capacity (by about 10% as I recall).
And the long version of a) & b) or 101 of disk drive servoing:
For atleast a decade, hard drives have used embedded servo patterns on every surface that are intermingled with the data areas. Using a dedicated surface for servo worked long ago only because track & data bit densities were much lower. Todays drives typically have 120 or more curved radial servo wedges that costs 5-7% of the surface area. User data tracks nestle between these servo wedges.
1) In these short servo wedge areas, servo tracks contain a few tiny fields of digital servo data followed by several analog modulations so that the servo processor can sense its fractional position within any servo track. Servo tracks actually abutt each other and the only bit change between adjacent servo tracks is in the Gray coded track no. Since IBM patented this many years ago (1980's ?), manufacturers have since added proprietry extra small digital fields to correct for read errors in the digital fields & analog modulations to continuously improve servo tracking and hense improve data track densities.
2) The user data tracks are not neccessarily pitched to be inlign with servo tracks and may be reduced to 2/3 the density of servo tracks. This provides guard space and reduces inter track symbol interference. As the disk spins from servo wedge area on into user data area, it becomes an increasing act of faith that the read head or the write head is indeed still following a track center until we reach the next servo wedge. Such miss tracking is called runout.
A major source for Non-Repeatable Runout comes from worn bearings which introduces random wobbling, and this degrades the servoing and limits tracks densities.
Fluid bearings improve upon ball bearings because they don't introduce this NRR so spinning is quiter but more importantly track densities can keep climbing.
There are quite a few other NRR & RR terms impacting on servo tracking.
Intelligent life would be dotted in time (throughout billions of years) as much as in space. Even long surviving species would be miniscule relative to the 10 plus ?? billion years of the galaxy. Even if such lucky planets have multiple extinctions and can repeat the occurance of intelligent life, the odds improve only a bit. What percentage of all such intelligent life is around right now in our blink of time ?. If our window of observational and communication interest is say some 5 thousand years, then out of a snapshot of 5 billion years of cosmic life, we've reduced the likelyhood of current intelligent life elsewhere in our galaxy by a million or so (give or take a zero). Time is as much a distance as space.