Abstract: Provided are a method and apparatus for providing serialization support for computer systems and computer system resources, in particular for application programs which require sequencing and/or consistency of data. The computer system resource includes serialized processes with units of work. A serialization token is provided at the start of a serialized process including at least one unit of work. The serialization token remains in force until the or all of the units of work of the process have been committed or rolled back. The serialization token controls the commencement of other processes of the computer system during the time that it is in force. The serialization is carried out by storing an abstract representation of the process to be serialized in storage which is accessible by all the programs and computers where the serialization applies.

Abstract: Provides data and program integrity in a computer system by guarding against malicious program operation when using the Branch In Subspace Group instruction (BSG) of the S/390 computer architecture. System integrity is ensured by providing a controlled target space (a base space) and branch address during a BSG transfer of control (branch) from a subspace, and a different PSW key mask (PKM) for the base space than for subspaces. More specifically, (1) the PKM is reduced and a new PSW access key is set during a BSG branch from the base space to a subspace, (2) the original PKM and access key and also a return address are saved in a secure data area during the same branch, and (3), during a branch from a subspace, the original PKM and access key are restored, and the branch is made to the return address (the controlled branch address) in the base space.

Abstract: There is disclosed a pressure-drop sensor valve system for controlling the movement of a fluid operated, ram-type device, such as that used to drive a panel punch. The valve-like device includes a main passage having an inlet for pressurized fluid and an outlet connectable to the ram-type device. Disposed intermediate said inlet and outlet is a fluid chamber. A poppet valve is positioned between said fluid chamber and an accumulator chamber in the body of the device. A fluid by-pass is connected to the fluid passage and a reservoir, and is blocked when the poppet valve is closed and opened when said valve is opened. A piston member is provided with its stem in the accumulator chamber opposite the poppet valve, both said member and valve being slightably movable by separate compression springs. A check valve is positioned in an axial passage of the poppet valve.