BACKGROUND Routinely collected databases are kept for administrative purposes. We have refined the analyses of the Swedish National Patient Register and the Cause of Death Register and explored their validity to monitor stroke at the population level. METHODS First-ever strokes (incident cases) and all stroke events were measured by combining the two administrative registers and adding refine...

It is well known that in an asynchronous message-passing system, one can emulate an atomic register providing that more than half of the processes are non-faulty. By contrast, when a majority of the processes may fail, simulating atomic register is not possible. This paper investigates weak variants of atomic registers that can be simulated tolerating a majority of processes failures. Specifica...

This paper presents an algorithm for implementing a k-ary regular register (the logical register) using k(k -1 )/2 binary regular registers (the physical registers) that requires only one physical write per logical write. The algorithm is simple to describe and depends on properties of paths in a related graph. Two lower bounds on the number of registers required by one-write implementations ar...

Assessment of exposure to airborne endotoxins has been studied for several years, especially in occupational environments, but a large number of procedures are used for sampling and analysis. This lack of standardization makes it very difficult to compare results and set internationally accepted threshold limit values (TLVs) or occupational exposure limits (OELs) for endotoxin exposure. This pa...

Many architectures require that a program use pairs of adjacent registers to hold double-precision oating-point values. Register allocators based on Chaitin's graph-coloring technique have trouble with programs that contain both single-register values and values that require adjacent pairs of registers. In particular, Chaitin's algorithm often produces excessive spilling on such programs. This ...

We propose a new system-level abstraction, the lightweight immutable execution snapshot, which combines the immutable characteristics of checkpoints with the direct integration into the virtual memory subsystem of standard mutable address spaces. The abstraction can give arbitrary x86 programs and libraries system-level support for backtracking (akin to logic programming) and the ability to man...

This paper presents the current state of our work on an interactive toplevel for the OCaml language based on the optimizing native code compiler and runtime. Our native toplevel is up to 100 times faster than the default OCaml toplevel, which is based on the byte code compiler and interpreter. It uses Just-In-Time techniques to compile toplevel phrases to native code at runtime, and currently w...

We present the internals of QEMU, a fast machine emulator using an original portable dynamic translator. It emulates several CPUs (x86, PowerPC, ARM and Sparc) on several hosts (x86, PowerPC, ARM, Sparc, Alpha and MIPS). QEMU supports full system emulation in which a complete and unmodified operating system is run in a virtual machine and Linux user mode emulation where a Linux process compiled...

This paper presents an extension of Necula and Lee’s Proof-Carrying Code (PCC) system to support the x86 architecture. PCC is a security scheme which allows the safe execution of untrusted code. Untrusted code to be executed is required to be coupled with a proof that the code satisfies certain safety properties. This code-proof pair is statically checked by the client system prior to execution...