Java steals software spotlight
Electronic Engineering Times
December 22, 1997
Alexander Wolfe
In the often-confusing world of software, Java stood out as the clear
focus of industry attention in 1997. Driven by engineers' demands for
improved performance, Java's leading proponents introduced technologies
to speed execution and prove to developers that the language is ready to
cut its teeth in real-world applications.
As a result, Java shed its early image as an overhyped newcomer and
became a real-world programming language that drove activity on the
Internet in general and network computing in particular.
Led by Sun Microsystems, software houses paved the path to the future of
Java by debuting optimization methods to make Java programs run faster.
In addition, several companies introduced compilers that convert Java
applications straight into X86 machine code.
On the silicon front, Sun Microelectronics, the semiconductor-technology
arm of Java inventor Sun Microsystems Inc., taped out its PicoJava core.
The core is the basis for several families of Java-specific
microprocessors that will be fabricated by NEC Corp., LG Electronics and
Rockwell. In early 1998, the chips will hit the market and shortly
thereafter are expected to start appearing in dedicated Web browsers,
network-computers and other low-cost Internet appliances.
While Java silicon could well dominate the scene by the end of 1998, the
focus over the next few months will continue to be on improvements in
software. Here, the highest-flying new technology is the Hot Spot
optimization approach from Sun Microsystems. (Sun acquired the Hot Spot
technology earlier this year when it purchased software developer
Longview Technologies of Palo Alto, Calif.) Hot-Spot forms the heart of
a compiler, which analyzes an application and identifies slow-running
blocks of code. These blocks are then compiled into native code, rather
than interpreted, for fast execution.
Sun is also hard at work on a radically revamped Java Virtual Machine
that will incorporate Hot Spot. A Sun official said an early release to
developers should be ready in early 1998, though the official launch to
the company's customer base won't come until next summer.
Of more immediate aid to software developers is the cutting-edge effort
at Symantec Corp. (Cupertino, Calif.), which promises the first of a
wave of fast native compilers that convert Java programs straight into
X86 machine code.
Such compilers could go a long way toward closing the performance gap
between Java and rivals like C and C++. Yet they're practically heresy
for a language that has built its appeal by promising developers they
could write a single platform-neutral program that would run on a PC,
Mac or Unix machine. However, the boost provided by direct compilation
is proving too great to pass up. As a result, Java religion is beginning
to yield to reality.
Symantec's compiler, which appears in its Visual Cafe 2.0 and Cafe Pro
2.0 Java development environments, directly translates Java source code
into native Windows. According to the company, the resulting machine
code is 25 percent to 50 percent faster than that generated by a more
conventional just- in-time Java compiler. As a result, it makes Java
programs much more competitive with code written in the C++ programming
language.
So-called native-compilation techniques such as Symantec's are gaining
adherents because they result in maximum execution speed with a minimum
memory footprint. In the middle ground lie just-in-time compilers. These
maintain Java's vaunted platform independence while reducing the
performance penalty, but also cause programs to bloat and take up more
memory.
The poorest performance comes from the old-line approach where byte
codes are interpreted by a software-based Java Virtual Machine. Indeed,
anecdotal reports peg interpreted Java applications at from two to 40
times slower than equivalent programs written in C++
The approaches being pursued by Sun, Symantec and Microsoft are expected
to push Java to new heights. Kevin Nilsen, president of the real-time
software developer Newmonics Inc., said he believes that Java will
ultimately be within 50 percent of the speed of C++ "Remember, these are
the eventual targets and right now the Java compilers and tools are very
immature, " he noted. "But the people we talk to seem to be willing to
pay these performance costs if they can get the productivity gains
associated with Java. "
While Java software steals the limelight, the long-term staying power of
the language will likely rest on whether Java silicon finds a ready home
in the market. In 1997, CPU designers did their part to make sure that
would happen. The first microprocessor to directly execute the Java
instruction set was unveiled this past fall by an unexpected source:
avionics manufacturer Rockwell Collins Inc. (Cedar Rapids, Iowa)
Because the chip features an unexpectedly low power-consumption rating
of only 60 mW average, it could help drive Java squarely into the
mainstream of embedded computing.
Interestingly, Rockwell, which has Java cross-licensing agreement with
Sun, did not use Sun's PicoJava core to create its low-power embedded
part. Instead, Rockwell engineers relied on the company's existing
Advanced Architecture Microprocessor (AAMP), which is a CPU family that
is constructed from an off-the-shelf library of standard cells.
Rockwell engineers said they made the choice because the architecture of
the AAMP microprocessor is very similar to the Java architecture. As a
result, it was easy for Rockwell to take its existing technology, make a
few tweaks and add new microcode and thus implement Java directly.
The result is a processor called the JEM1, which runs at 50 MHz and is
implemented in Rockwell's 0.5-micron CMOS process technology. The JEM1
core sits on only 6 mm2 of silicon real-estate and is combined with an
interrupt controller, two programmable timers, external data-bus
support, power- management technology and a JTAG test-interface to form
a complete processor.
JEM1 is the first of a planned family of Java devices from Rockwell,
which could include parts fitted with additional peripheral features.
Rockwell believes JEM1 could find a home in heavy-duty embedded
applications such as the company's own avionics systems.
While Rockwell was first to market, the center of Java silicon efforts
remains Sun Microelectronics. The company is planning a trio of Java
chips dubbed PicoJava, MicroJava and UltraJava. Sun is well along in the
design process. Even so, the chips have yet to be shipped and they have
remained the subject of intense interest ever since the processors were
first discussed by Sun a year ago.
In PicoJava, which is aimed at the embedded market, Sun is addressing
performance via the inclusion of a hardware JVM that enables Java byte
codes to be executed directly by the chip without passing through an
interpreter. To facilitate embedded applications, PicoJava is also being
outfitted with extra instructions-called extended byte codes-not found
in the standard Java instruction set.
These correlate directly to low-level chip-control operations such as
register accesses, cache control and load and store operations. In
practical usage, the extended byte codes are supposed to make it easier
to control modems and network-interface devices. To speed performance,
the extended byte codes can be executed directly by PicoJava in the same
way it handles standard Java instructions. Two companies that have
licensed Sun's PicoJava core-LG Semicon and NEC- are expected to have
devices in the spring. Mitsubishi and Samsung also have Java licensing
agreements with Sun Microelectronics, though it is not clear what plans
the respective companies have.
For its part, Toshiba is using the Sun core to develop a low-power Java
chip. In addition, Siemens will embed Java technology in smart cards.
But Patriot Scientific Corp. beat Sun and its partners to the punch, unveiling its PSC1000 Java chip this past September.
Copyright (c) 1997 CMP Media Inc. |
