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| Structured Streams: A New Transport Abstraction |
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Google Tech Talks
November, 27 2007
Internet applications currently have a choice
between
stream and datagram transport abstractions.
Datagrams
efficiently support small transactions and
streams are
suited for long-running conversations, but
neither
abstraction adequately supports applications
like HTTP that
exhibit a mixture of transaction sizes, or
applications like
FTP and SIP that use multiple transport
instances.
Structured Stream Transport (SST) enhances
the traditional
stream abstraction with a hierarchical
hereditary structure,
allowing applications to create lightweight
child streams
from any existing stream. Unlike TCP streams,
these
lightweight streams incur neither 3-way
handshaking delays
on startup nor TIME-WAIT periods on close.
Each stream
offers independent data transfer and flow
control, allowing
different transactions to proceed in parallel
without
head-of-line blocking, but all streams share
one congestion
control context. SST supports both reliable
and best-effort
delivery in a way that semantically unifies
datagrams with
streams and solves the classic "large
datagram" problem,
where a datagram's loss probability increases
exponentially
with fragment count. Finally, an application
can prioritize
its streams relative to each other and adjust
priorities
dynamically through out-of-band signaling. A
user-space
prototype shows that SST is TCP-friendly to
within 2%, and
performs comparably to a user-space TCP and
to within 10% of
kernel TCP on a WiFi network.
Speaker: Bryan Ford, PhD CS MIT (June 2008)
PhD Advisor: Frans Kaashoek
Tags : google techtalks techtalk engedu talk talks googletechtalks education |
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Affichage : 2651
Durée : 3777 s |
| Paradigm Regained: Abstraction Mechanisms for Access Control |
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Google TechTalks
July 12, 2006
Mark Miller
Open Source Coordinator E Project at
erights.org Dr. Miller is a designer of
several distributed secure programming
languages including Vulcan for Xerox PARC,
Trusty Scheme for AutoDesk, Joule for Agorics
and Fujitsu, Tclio for Sun Labs, and E for
Electric Communities, ERights.org, Combex,
and HP.
ABSTRACT
The first Authorization Based Access Control
(ABAC) model dates from Dennis and van Horn's
1965 Supervisor. Strikingly, their paper does
not mention security as a separate concern.
Rather, they considered modularity, naming,
abstraction, composition, and security as
inherently related problems, to be
simultaneously addressed by a unified set
of...
Tags : google howto paradigm regained abstraction |
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Affichage : 506
Durée : 3605 s |
| CS 61A Lecture 9: Data Abstraction, Sequences Calculator I |
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CS 61A - Spring 08 - The Structure and
Interpretation of Computer Programs
Instructor Brian Harvey
Introduction to programming and computer
science. This course exposes students to
techniques of abstraction at several levels:
(a) within a programming language, using
higher-order functions, manifest types,
data-directed programming, and
message-passing; (b) between programming
languages, using functional and rule-based
languages as examples. It also relates these
techniques to the practical problems of
implementation of languages and algorithms on
a von Neumann machine. There are several
significant programming projects, programmed
in a dialect of the LISP language.
http://www.cs.berkeley.edu
Tags : CS 61a data abstraction sequences harvey ucberkeley lecture |
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Affichage : 413
Durée : 3070 s |
| CS 61A Lecture 10: Data Abstraction, Sequences Calculator II |
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CS 61A - Spring 08 - The Structure and
Interpretation of Computer Programs
Instructor Brian Harvey
Introduction to programming and computer
science. This course exposes students to
techniques of abstraction at several levels:
(a) within a programming language, using
higher-order functions, manifest types,
data-directed programming, and
message-passing; (b) between programming
languages, using functional and rule-based
languages as examples. It also relates these
techniques to the practical problems of
implementation of languages and algorithms on
a von Neumann machine. There are several
significant programming projects, programmed
in a dialect of the LISP language.
http://www.cs.berkeley.edu
Tags : CS 61a data abstraction sequences harvey ucberkeley lecture |
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Affichage : 336
Durée : 2797 s |
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