MacOS内存和存储显示计算问题不准确

[zouchengli]

[0xJacky]

在 8f8cb6d 中，我修复了 macOS 下硬盘统计数据出错的问题，以我 1T 配置为例，输出的是 995GB (926GiB)，符合 df -h 的输出结果

df -h
Filesystem                         Size    Used   Avail Capacity iused ifree %iused  Mounted on
/dev/disk3s1s1                    926Gi    10Gi   153Gi     7%    426k  1.6G    0%   /
devfs                             350Ki   350Ki     0Bi   100%    1.2k     0  100%   /dev
/dev/disk3s6                      926Gi   3.0Gi   153Gi     2%       3  1.6G    0%   /System/Volumes/VM
/dev/disk3s2                      926Gi   6.7Gi   153Gi     5%    1.3k  1.6G    0%   /System/Volumes/Preboot
/dev/disk3s4                      926Gi   1.7Mi   153Gi     1%      56  1.6G    0%   /System/Volumes/Update
/dev/disk1s2                      500Mi   6.0Mi   481Mi     2%       1  4.9M    0%   /System/Volumes/xarts
/dev/disk1s1                      500Mi   5.4Mi   481Mi     2%      32  4.9M    0%   /System/Volumes/iSCPreboot
/dev/disk1s3                      500Mi   3.2Mi   481Mi     1%      70  4.9M    0%   /System/Volumes/Hardware
/dev/disk3s5                      926Gi   752Gi   153Gi    84%     12M  1.6G    1%   /System/Volumes/Data
map auto_home                       0Bi     0Bi     0Bi   100%       0     0     -   /System/Volumes/Data/home
OrbStack:/OrbStack                173Gi    29Gi   145Gi    17%       0     0     -   /Users/Jacky/OrbStack
/Applications/Weibo.app/Wrapper   926Gi   769Gi   139Gi    85%     14M  1.5G    1%   /private/var/folders/6c/5n5snlf17530r44clwjjt0_00000gn/X/431D1EE6-76BF-57F6-9369-582EF4B4E4F2

关于内存用量，以我的 32G 内存的 Mac 为例：

sysctl -n hw.memsize
34359738368

macOS 返回的物理内存总量，单位为字节 (bytes)

• 按 10 进制（1 GB = 10^9 B）换算约为 34.36 GB，四舍五入写成 “34 GB” 基本无误
• 按 2 进制（1 GiB = 2^30 B）换算恰为 32 GiB

References

• Super User – “Mac OS X sysctl get total and free memory size”
• Apple Support Community – “sysctl physmem vs memsize”
• Stack Overflow – “Determine physical mem size programmatically on OS X”
• Apple Stack Exchange – “How do I find out how many bytes of memory my machine has in RAM?”
• matisse.net Bit Calculator – 34359738368 bytes conversion
• ConvertUnits.com – Byte → GiB converter
• Flightpedia – “34359738368 Byte to Gigabyte”
• UnitConverters.net – Byte ↔ Gigabyte