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11 Cards in this Set

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What resources are inherited acros
-PID and parent PID
-real UID and parent GID
-Session ID
-Controlling Terminal
-Time left until alarm signal.
-Pending (blocked) signals.
-cwd
-root directory
Review the kernel startup process.
1. BIOS begins executing, discovers devices, loads basic BIOS drivers, loads kernel into memory, transfers control to first instruction of kernel.

2. Kernel begins executing (possibly decompresses).

3. Kernel Initializes - memory is configured, interrupt vectors are set up. Device drivers initialized. Scheduling started. Printk("ag Burgers") from lab 1. Start kernel threads. Start the first process.
What is the name of the first process that is the parent of all other processes in UNIX?
init.
What are threads?
Threads are multiple execution contexts within a single process.
What resources are unique to a thread and what resources are shared between threads?
Unique to a thread:
-CPU registers (general purpose, PC)
-Stack
-State

Shared between threads:
-Address space (global, static vars)
-open files
-child procs
-signals,pending signals, signal handlers
-accounting information
What are the benefits of threading?
-Easy way to support concurrent users.
-Easier to create
-Performace enhancement
What is the biggest benefit of threadsover processes?
Synchronization overhead.
What are two design patterns for working with threads?
-Manager/worker
-Pipeline
What is a non-reentrant system call?
A non-reentrant system call is one that cannot be called simultaneously from within the same process.
Name two types of thread models.
Kernel threads and user threads.
What are the pros and cons of user threads?
Pros:
-Smaller overhead
-more control over scheduler
-somewhat more portable

Cons:
-One blocking system call blocks entire process
-Doesn't provide multi-core or multi CPU support
-handling signals is difficult