Transcript Computers for the 21st Century - Computer Science & Engineering

The Tablet PC at Five
Chuck Thacker
Distinguished Engineer
Microsoft Corporation
July 20, 2005
Talk outline
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Tablet history
The Tablet today
Tablet futures
Limits on computers
– What Moore actually said.
– Implications for computers.
– Other limits
• What about software?
• Conclusions
Prehistory – before 2000
• Lots of earlier attempts – mostly failures.
– DEC, Go, Newton, Pen Windows
• Technology wasn’t ready
• But vertical markets had limited success.
• Needed: better UI, better handwriting
recognition (without relying on it).
• Key: Better digitizer (with hover).
An earlier attempt -- 1983
• TRS 80 Model 100
• Reporters and students
loved it
• Ran for days on AA cells
• Solved most computing
needs for its (low
aspiration) users.
Another attempt -- 1993
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DEC Lectrice
5.5 pounds
1.5 hour battery
Wireless network
$5K LCD panel
VxWorks OS, X11 server
optimized for reading
Where we started: Internal MS (1999)
• Microsoft proof of concept
– Transmeta TM5800
– 256MB DRAM, 20GB HDD
– 10.4” Slate
• Good points:
– Proved viability
– Pushed the Power Efficiency Envelope
• 5 Hours runtime, 200 Hours standby
– Provided a development platform
to get MS to Tablet PC launch.
• On the Other Hand:
– It was so sloooooow
Today’s Market: New Slates
Motion
Computing
Sahara i213
12.1”, 1.6GHz
Centrino
LE
1600
NEC
VersaPro, 10.4”,
1.1 GHz
Fujitsu 5000
Tatung TTAB
10.4”, 1 GHz
ULV
LS
800
10.4/12.1,
Indoor/Outdoor
1.1 GHz ULV
Tatung B12D
12.1” 1.2 GHz
Centrino
Today’s Market: New
Convertibles
Acer
Toshiba
M200, 12.1”
SXGA+
C1xx
C300
Gateway
M275
2 GHz
Pentium-M
14.1”, DVD
Fujitsu
1.8 GHz
Pentium-M
Averatec
C3500
AMD 2200+
12.1”, DVD
Electrovaya
1.4 GHz Centrino
T4000
12.1”, Biometrics
C250
Scribbler SC-2200
SHARP
ViewSonic
12.1”, 1 GHz
Actius TN10W
12.1”, 1.1 GHz
IBM
ThinkPad
x41
HP
tc4200
Today’s Market: New Hybrids & Ruggeds
Ruggedized
Hybrid
Itronix
HP Compaq TC1100ULV
8.4”, 933 MHz ULV
Walkabout
Hammerhead
Celeron or Pentium
10.4”, 1.1 GHz
10.4”, 4.5 lbs
933 MHz P-III M
Xplore iX104
10.4” 1.1 GHz ULV
Concept Design: New hinge
A Concept Tablet for Kids
• Low power
– (7W)
• 8.4” display
• Tethered pen
• Rugged
Other Form Factors
OQO Model 1
Vulcan FlipStart
Today’s Market: Forecasts
• Mobile Market Projections (IDC)
Ultra-Mobile
0 to 1 spindle, 5-8” screen, < 2 lbs.
Ultra-Portable
1 or 2 spindle,10-12” screen, 2-4 lbs.
Thin & Light
2 spindle, 14-15” screen, 4-7 lbs.
Transportable
2 & 3 spindle, 14-17” screen, 7-12 lbs.
2004
2006
2008
Market share
Market share
Market share
1%
3%
17%
31%
63%
63%
56%
Information Workers,
30%
Consumers
CY08 Market: 8.9M, CAGR (04-08): -11%
19%
10%
Consumers,
Mobile Professionals
CY08 Market: 2.5M, CAGR (04-08): 40%
0%
Mobile Professionals,
8%
Information Workers
CY08 Market: 28.4M, CAGR (04-08): 51.4%,
Information Workers,
Consumers
CY08 Market: 51M, CAGR (04-08): 22%
Moore’s Law (1967)
• Not really a “law”, but an observation,
intended to hold for “..the next few years”.
• (Nt/A)(t1) = (Nt/A)(t0) * 1.58t1-t0 (t in years)
• Most exponential curves in the real world
turn out to be “S” shaped, but Moore’s
observation has held for 35 years.
The Woolly Bear Book of VLSI scaling
• Scaling requires lithography and process changes.
• Get more and faster transistors in the same area.
• Power per transistor goes down, power per unit area
goes up (sometimes way up).
• Power ≈ CV2f (plus leakage)
How to use Moore’s Law
• Lower cost: Same Nt, reduced A (“die
shrinks”) used in video consoles.
• More complex chips: Larger Nt, same A.
– Lower the voltage and increase frequency
– Add larger caches to overcome latency
– Add architectural features to increase ILP
• Superchips (SOC): Increase Nt and A.
Moore’s Law for Memory
• Capacity improvement: 1,000,000 X since
1970.
• Bandwidth improvement: 100 X.
• Latency reduction: only 10-20 X.
– Dealing with latency is the largest problem for
a computer system designer.
Moore’s Law for Processors
• More complex designs
• More than one processor on a chip
(homogeneous).
• More than one processor, with specialized
functions, e.g. graphics
– Graphics performance is improving much
faster than CPU performance.
Thirty years of progress
Item
Alto,
1972
MS Tablet
2002
Factor
CPU clock rate
6 MHz
600 MHz
100
Memory size
128 KB
256 MB
2000
Memory access 850 ns
time
100 ns
8.5
Display pixels
606 x 808 x 1
768 x 1024 x 16
1.5 (x16)
Network
3 Mb Ethernet
100 Mb Ethernet
30
Disk capacity
2.5/5 MB
6 GB
2400/1200
Possible Future Limits
• Physical limits:
– “Atoms are too large, and light is too slow”
– Today, the problem isn’t making the transistors faster, it’s the
time for signals to propagate on the wires (latency again).
– Power. Lots of transistors => lots of power. Cooling is hard.
• Design complexity:
– Designing a billion-transistor chip takes a large team, even with
good design tools.
– The “junk DNA” problem.
• Economics:
– Factories are very expensive.
Scaling Limits
• Voltage scaling is about over. It’s very
hard to operate below 1 volt.
• Frequency increases are also difficult.
– Intel runs out at 3 – 4 GHz.
• Static leakage is also a big problem.
• So, we’ll see more transistors in the future,
but they won’t be better or faster
transistors.
Future processors
• We’ll see chips with many processor cores.
• Each core will be simpler than today’s
superscalar machines. Probably hyperthreaded,
to hide latency.
• Optimized to increase thread-level parallelism,
rather than instruction-level parallelism.
• The story about caching is very unclear…
• See Intel’s “Platform 2015” white papers.
Other Limits
• Not all technologies used in computers
follow Moore’s Law
– Disks don’t
– Displays don’t
– Batteries don’t
• The bandwidth vs. latency problem.
– See D. Patterson, “Latency Lags Bandwidth”,
CACM, October 2004
What about software?
• For scientific computing and servers, the
future seems fine.
– There are lots of important problems that are
embarrassingly parallel.
• For client software, the picture is more
bleak.
Many-core challenges for clients
• Windows doesn’t use threads well
– Exceptions: Kernel, SQL
– Competitors don’t do any better
• Applications don’t use threads well
– Outlook is the poster child
– Until recently, inking on Tablet was problematic
• Problems:
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Writing multi-threaded code is hard
Threading model and primitives are overly complicated
Threads don’t compose
Debugging multi-threaded code is harder
Testing multi-threaded code is a crapshoot
Tool support isn’t very good
Possible paths forward
• Better language support for parallelism
– Cω, Atomic transactions
• Better tools
– Analyze liveness and safety statically
– Model checking
– Dynamic race detection
• Better libraries
• Better education
Conclusions
• Popularity of portable devices, including
Tablet PC, is growing
• Much of the innovation in the industry is in
this area.
• Energy-efficiency can open up new
markets.
• Silicon trends favor the high end
• There are lots of challenges and
opportunities for new software.