Transcript ppt - UCL Computer Science

Scaleable Ubiquitous Systems
“3 should be enough – 1 or 2 in the
US and 1 in England”…(ok,
Scotland)…
Scaleable Ubiquitous Systems
Research
Some CS Systems Grand Challenges
[email protected]
http://www.cl.cam.ac.uk/~jac22
Grand Challenges
• UK CRC (CPHC, RC, BCS, IEE) prompted
by US
• List 100s of …select >= 0
• CPHC Conf in Spring 04 will say more
• On Web Site…(google…)
• Multipurpose – just get $? Well, no – but 
• E.g. Put a robot on mars, bring it back
alive…
This challenge…
• Computers will vanish…into the material world
• Need to be as robust or predictable as a table or
chair is or more so…
• Will be networks (embedded systems to date are
not)
• Like insects, there are as many of these per per
person, as there are people
• i.e. Internet ^ 2, or an Internet of Interstitial
Internets
Lets scope the problem to 10 year
• So we don’t go mad
• What can we realistically achieve?
• Btw, pervasive, ambient, sentient, ubiquitous,
vanishing, invisible computing is not a new
“challenge”
• It may not be a “challenge” per se at all: for
example, merely sustaining Moore’s Law (and
equivalent for storage and network capacity) is not
regarded as a challenge by other science and
engineering disciplines, although we all know it
is
Ubiquity&Environment 1
Assumptions – extend scale down and up
First Down:
• Epsilon power
• Limited traditional resources (comms, cpu,
memory)
• Very low (range, and variability) MTBF, high
MTTR of components
• But: do assume a large“infrastructure” nearby
• (i.e. not, absolutely NOT, ad hoc self org)
Ubiquity&Environment 2
Assumptions – extend scale down and up
And then up:
• 1000 powered devices per person
• Terabytes of store per person per year
• Fixed network capacity Gbps per person 24*7
• MTBF 100 year line, disk, cpu – fault tolerance
models need to be extended
Criteria for Ubiquitous Systems
•
•
•
•
Programmable by “naïve” user
Operate continuously in evolving environment
Scale to 10^12 nodes – measure \(IMW) ubiq.
Trustworthy (“proof of behaviour” carrying code)
– I.e. use Theory – e.g. stochastic process
algebras
• Sustainable, Adaptable, Multipurpose
• Concept of Transparencies revised from
ODP…accuracy+certainty derived from…theory
of…expresses principles (e.g. e2e, parsimony, soft
state, etc etc…)
Benefits of Ubiquitous Systems
• Empowers some users (c.f. normal humans)
• Empowers some applications
• I.e. economic in some sense, although for some
(e.g. support for field work, whether science,
medicine or what have you) not doable
• Incorporate range of intermediaries for pipelines
of transforms (lego like) etc
• Lots of Human Computer Interaction research
required
Needs from CS &other
disciplines
• theory – need to accommodate theory of ubi
systems – e.g. location, reliable, e.g. Need
to work between network calculi and
process calculi
• Users need to tell us what new model of
transparencies are!!!
• exemplars act as a clock for systems
work…
Information Theory applies
• Code must be executed redundantly ,but not
greedily!!)
• Data must be stored (and moved) in some FEC
manner (c.f. eternity/pastry etc) (DHT, Rabin
Fingerprint, stripe/wraid)
• Transmission need to deal with lowering
overheads, adapting to circumstance and
converging in determined time (e.g. routing etc)
• Aggressive use of intermediaries to cache,
transform –
• Power, location, identity and ownership are a first
class member of (meta) data, code, node, etc
System is reflective
• Can monitor and reason about (and report) its own
behaviour and esp. performance (e.g. accuracy,
timeliness etc) and failures
• Can reason about trust in system from h/w up (viz
TCB will be here before mid way through GC)
• Goal is Highly Optimized Tolerance (see Doyle) –
we cannot afford phone net engineering
• Control theory needs to be extended
• Perhaps use automated reasoning etc etc
Other problems…
• Couple of other thoughts about meta-problems
• Need location of data and code as 1st class tag; but
include: provenance (principles/capabilities) in
some (many?) applications to feed into user
confidence. TRUST
• Need some sort of system economics (of
combined data, processing and communications)
AFFORDABILITY
Some bits we are doing…
1. Economical Security - stochastic
mechanism design!
2. Containment - “not-quite” location based
computing
3. Mobility Models and IMW for Ubi
4. Mixed Reality Processing Models
5. Net/OS
1 Economics bit…
• Mechanism design deals with aligning incentives
• But often assumes perfect information in market
• We have a model for providerless networks, using
dual algorithm (c.f. kelly, tomorrow)
• For battery, transmit, store, cpu etc…
• Needs more theory to cope with uncertainty
otherwise not strategy proof (or needs possibly
complex witness/enforcement system)
2 Containment
• We attach containment (position relative to
physical surroundings) as a first class
attribute of all objects (OS, Device)
• All I/O is typed w.r.t transmission media
(IR, RF, Visible, Audio, etc), and so are
containers
• Seems quite nice model for reasoning about
privacy for example
3 Mobility Models
• Most paperson mobile use extremely naïve
mobilty model (random)
We have data from road and pedestrian
monitors (real time (1 sec) road every 500
yards of whole UK, pedetrian - anonymized
film of streets of much of London with head
tracking!)
• …but its rather a lot to process right now!
4 Mixed Reality Processing
• Esp. good for sensor nets
• Embed physical model in high level program
• Position/locate sensors - compile program into set
of functions for delta encoding
• Note most physical signals travel@speed<<C but
net can propagate info (via directed diffusion) at
C, so can then just compute difference on model
and only send delta above threshold - nice for
handling impluses and congestion
5 Operating System&Comms
“Stack”
• What is minimal unit we “boot” – pico/nano
hypervisor (xen) kernel
• What is the VM of a set or subset of nodes that
present a traditional “computer” to the world (I.e.
is hierarchical decomposition of function still ok
or do we need new model (components in a graph
combine to provide overall service – e.g. store an
object, deliver a sense…etc)
• Operating Systems need to be revisited (symbian
exploded?)
Exemplars
• “See sentient building, street, hospital, city, planet,
solar system, etc
– Path lab with sensors
– 0 road deaths
– Cradle-to-grave health record indexed by location and
time (epidemiology, evidence based health, pathology,
remote intervention)
– As scale increases, start to move to 100% environment
awareness (see Snow Crash), and beyond
Conclusions
• “The future is bright, the future is…”
• Not windows, IP, intel
• Whole new business in processor, OS,
network – Science (and then engineering)
• More importantly, whole new models for
systems, including a science, not just
engineering, and including people, not just
technology.