Computer implemented method for transferring command messages between a system manager for a computer system and a network operating system associated therewith

A computer implemented method for transferring command information from a system manager for a computer system to a network operating system associated therewith via an interface having at least one interface storage register for storing said command information during said transfer and a first interface control register for controlling said transfer of said command information, comprising the steps of:

• said system manager initiating a first use of said at least one interface storage register by setting a first bit of said first interface control register when said first bit of said first interface control register is not set;
• the prior contents of said first bit of said first interface control register transferring to a second bit of said first interface control register each time said first bit of said interface control register is set or reset;
• said system manager testing said second bit of said first interface control register, said at least one interface storage register being busy if said second bit is set and not busy if said second bit is not set;
• said system manager writing said command information to said at least one interface storage register in response to said testing indicating said at least one interface storage register is not busy;
• said second bit of said interface control register being set by an attempt to initiate a second use of said at least one interface storage register by setting said first bit of said interface control register while said first bit of said interface control register is set;
• said system manager informing said network operating system that said command information has been written to said at least one interface storage register;
• and
• said network operating system resetting said first bit of said first interface control register and reading said command information from said at least one interface storage register, said resetting of said first bit of said interface control register setting said second bit of said interface control register;
• wherein a subsequent use of said at least one interface storage register is initiated by setting said first bit of said interface control register, said setting of said first bit of said interface control register resetting said second bit of said interface control register.

A computer implemented method for exchanging command information between a network operating system and a system manager for a computer system associated therewith via an interface having at least one mailbox register through which said command information is exchanged and a semaphore register and first and second doorbell registers for controlling said exchange of said command information, comprising the steps of:

• said network operating system initiating a first use of said at least one interface mailbox register by setting a first bit of said semaphore register when said first bit of said semaphore register is not set;
• the prior contents of said first bit of said semaphore register transferring to a second bit of said semaphore register each time said first bit of said semaphore register is set or reset;
• said network operating system testing said second bit of said semaphore register, said at least one mailbox register being busy if said second bit is set and not busy if said second bit is not set;
• said network operating system writing a command message to said at least one mailbox register in response to said testing indicating said at least one mailbox register is not busy;
• said second bit of said interface control register being set by an attempt to initiate a second use of said at least one mailbox register by setting said first bit of said semaphore register while said first bit of said semaphore register is set;
• said network operating system informing said system manager that said command message has been written to said at least one mailbox register by setting said first doorbell register;
• said system manager resetting said first doorbell register, reading said command message from said at least one mailbox register and processing said command message read from said at least one mailbox register;
• upon completing said processing of said command message, said system manager setting said second doorbell register and placing error information in said at least one mailbox register;
• said network operating system reading said error information stored in said at least one mailbox register, resetting said second doorbell register and resetting said first bit of said semaphore register, said resetting of said first bit of said semaphore register setting said second bit of said semaphore register;
• wherein a subsequent use of said at least one mailbox register is initiated by setting said first bit of said semaphore register, said setting of said first bit of said semaphore register resetting said second bit of said semaphore register.

A computer implemented method for exchanging command information between a network operating system and a system manager for a computer system associated therewith via an interface having at least one mailbox register for storing said command information during said transfer and a semaphore register and first and second doorbell registers for controlling said exchange of said command information, comprising the steps of:

• said system manager initiating a first use of said at least one mailbox register by setting a first bit of said semaphore register when said first bit of said semaphore register is not set;
• the prior contents of said first bit of said semaphore register transferring to a second bit of said semaphore register each time said first bit of said semaphore register is set or reset;
• said system manager testing said second bit of said semaphore register, said at least one mailbox register being busy if said second bit is set and not busy if said second bit is not set;
• said system manager writing a command size to said at least one mailbox register in response to said testing indicating said at least one mailbox register is not busy;
• said system manager informing said network operating system that said command size has been written to said at least one mailbox register by setting said first doorbell register;
• said network operating system resetting said first doorbell register, reading said command size from said at least one mailbox register, allocating a buffer sized in accordance with said received command size, writing a buffer address for said allocated buffer to said at least one mailbox register, and informing said system manager that said buffer address has been written to said at least one mailbox register by setting said second doorbell register;
• said system manager reading said buffer address from said at least one mailbox register, resetting said second doorbell register, transferring a command to said allocated buffer and informing said network operating system that said command transfer is complete by setting said first doorbell register;
• upon completing said processing of said command, said network operating system placing error information in said at least one mailbox register and informing said system manager of said error information by setting said second doorbell register;
• said second bit of said semaphore register being set by an attempt to initiate a second use of said at least one mailbox register by setting said first bit of said semaphore register while said first bit of said semaphore register is set;
• said system manager reading said error information from said at least one mailbox register, resetting said second doorbell register and resetting said first bit of said semaphore register;
• and
• said resetting of said first bit of said semaphore register setting said second bit of said semaphore register;
• wherein a subsequent use of said at least one mailbox register is initiated by setting said first bit of said semaphore register, said setting of said first bit of said semaphore register resetting said second bit of said semaphore register.