moving them out of sight but not out of
existence. A system must still answer
a request, and the fewer instructions
programmers must provide to the system about what an application needs
(and where to find it, along with quantities to accept and cost in terms of
response time and resource consumption the application tolerates), the less
the system will provide what the sender of the request has asked for.
In real systems, a response to a request is rarely only a collection of information but much more likely a set
of desired behavior in time, cost, size,
Markus Kropf, Thun, Switzerland
Abstraction means hiding unnecessary
details, and most class libraries and
frameworks aim to hide specific details
to simplify programmers’ lives. However,
if these details are in fact relevant to an
application, then programmers should not
use the abstraction or hope the abstraction
is leaky (actually a good thing) such that
they can dive under the hood in case they
need to deal with lower-level concerns.
erik Meijer, Redmond, WA
This letter updates the Letter to the
Editor “Justice for Jahromi” (Nov.
2011) where I reported Masaud Jahromi had been imprisoned in Bahrain
for months, beginning last April, and
not permitted access to a lawyer or formally charged as to his crime and subsequent imprisonment.
The Jahromi family, which is aware
of the letter, says it greatly appreciates
ACM’s support and concern.
The new information I have re-
ceived is both encouraging and of
grave concern. For one thing, Jah-
romi’s exact title has been clarified.
He is a professor of telecommunica-
tion engineering and chairman of
the Telecommunication Engineering
Department of Ahlia University in the
Kingdom of Bahrain. The encourag-
ing news is he was released on bail
September 12, 2011, though it came
five months after his arrest. On Au-
gust 24, he was finally informed of the
single charge against him: “participa-
tion in an unauthorized rally.” The
concern is that, following the arrest,
false rumors were circulated that de-
stroyed his social and academic pres-
tige at Ahlia University and led to his
suspension from his positions there.
His lawyer says there is no official or-
der to suspend Jahromi, and he has
the right to be back on duty until the
day the court issues its verdict. How-
ever, the university has apparently re-
jected Jahromi’s request.
Jack Minker, College Park, MD
Correction: Bouyer figures found
Two in-text figures on pages 80 and
81 were inadvertently dropped from
the print version of Patricia Bouyer
et al.’s Review Article “Quantitative
Analysis of Real-Time Systems Using
Priced Timed Automata” (Sept. 2011).
The complete version is now available
through the ACM Digital Library (http://
and Communications Web site (http://
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less, and send to firstname.lastname@example.org.
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