Encryption refers to the process of transforming data into a form that is unreadable, unless the reverse process of decryption is applied. Encryption algorithms use an en- cryption key to perform e...

Terminologies 导空: \(X\) 可导空意味着 \(X \Rightarrow^* \varepsilon\)。 句型: a set of symbol string that can derive from start symbol. 句子: a set of terminal string that can derive from start sy...

Grant privileges Syntax GRANT <OPERATION> ON <TABLE> TO <USER> [<USER1> <USER2> ...] [WITH GRANT OPTION]; <USER> 可为 PUBLIC，意为所有人。注意：使用 PUBLIC 授予权限，意味着未来创建...

Permissions: PTE_R allows page to be read. PTE_W allows page to be written. PTE_U allows page to be accessed by user. PTE_V left clear in unused PTEs, which seems to be VALID flag. Thing...

C -> Asm / processors Every processor has an associated instruction set architecture (ISA) C -> Asm (.S) -> .o files -> executables RISC-V & x86-64 x86-64 3 full books ...

Terms PRIME render offload PRIME render offload is the ability to have an X screen rendered by one GPU, but choose certain applications within that X screen to be rendered on a different GPU. DR...

Address spaces An address space is the range of memory addresses that a process can reference. Memory management unit Between CPU and memory, there is memory management unit (MMU), which transla...

Some registers that may help work out the error in riscv: scause (Supervisor Cause Register) indicates the type of the page fault. sepc: Supervisor Exception Program Counter stval (Superviso...

Isolation Real world examples Think in Strawman design: If no operating system, there is no strong isolation between programs. Unix interface abstracts the hardware resources. processes: ...

This lab requires python<=3.12 (to import module pipes). I’d like to record my process of implementing primes.c. At first, I didn’t know that subprocess who forked from the parent should clos...