# General Feature

* ram size:
* 128 Mbite

* page table size:
* 4096

* boot sequence
* 0x8000_0000

### Scheduler

### `param.h`
* Fixed Limits
* Several Arrays
* `kill(pid)`

* what is a page
* find argc and argv on the stack

### page table
* Sv32
* Sv39 (xv6)
* Sv48
#### virtual address size:
##### Sv39
* 39 bits
* 2 ^ 39 = 512 Gbites = 0x80_0000_0000

##### xv6 only use 38 bits
* 38 bits
* 2 ^ 38 = 256 Gbites (0x40_0000_0000)
= `MAXVA`
* address range: 0 ~ 0x3f_ffff_ffff