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Let's get started… In Gem #97, a reference-counting pointer was presented, where a Get function returns an access to the data. This could be dangerous, since the caller might want to free the data (which should remain under control of the reference type). In this Gem, we present a method to prevent the misuse of the result of Get.
Access types in Ada have been designed in a way to prevent the occurrence of dangling references, i.e. they cart never designate objects that have gone out of scope. There remains however one problem: W h e n U n-c h e c k e d D e a l l o c a t i o n is used in order to reclaim storage, we might access already freed storage or, even worse, storage occupied… (More)
A large and dark room. In the foreground a terminal, at the rear wall a huge screen showing everything that happens at the terminal. At first the screen is off, the room in twilight. Below the stage, but visible, Lady Ada in a coffin. Around the stage on a gallery, nearly invisible in the dark (also when the stage is lit), the chorus of Ada gurus.
With its tagged types and appropriate dynamic binding facilities, Ada95 has become a mighty language. Virtually ad libidum, you can add new components to given types of a class. This seems to imply some kind of arbitrariness in the choice of the starting point of a type hierarchy (the root of a class). However, this arbitrariness is only a seeming one and… (More)
An ultra wideband MMIC low noise amplifier (LNA) based on the 0.15-μm pHEMT 3MI Triquint power process has been demonstrated. A feedforward noise cancellation technique was employed to reduce the thermal noise in the LNA. The LNA has a surface area of 2 mm by 2 mm. The gain of LNA is 15 dB between 400 MHz and 12.5 GHz with ±0.3dB gain flatness… (More)
Let's get started… In Gem #107, we presented an accessor for safely referencing objects stored in a container. The example concerned a reference-counted pointer, but such accessors can be defined on any kind of container. An advantage of using accessors rather than simple access types is that the former cannot be used to deallocate the designated object.… (More)
The investigation of the fracture behavior of polymers in the environmental scanning electron microscope (ESEM) can provide information about the correlation between the microstructure of a specimen and the macroscopic stress-strain characteristic. As the mechanical properties of polymers change dramatically at the glass transition temperature, cooling of… (More)
Intention der Fachgruppe: Software garantiert häufig direkt die Sicherheit für Menschen. Ada wird in internationalen Sicherheitsstandards empfohlen und unterstützt in einzigartiger Weise moderne Analyse, Design und Programmiermethoden und damit die Entwicklung großer zuverlässiger Software-Systeme. Die Fachgruppe will über die Konzepte von Ada und deren… (More)