300 系列好像是 linux base 的
http://www.smallbusinesscomputing.com/news/article.php/3904856/Cisco-Rolls-Out-New-Linux-Switches-for-Small-Business-Networks.htm

http://www.cisco.com/c/dam/en/us/td/docs/switches/lan/csbss/slm2024/administration/guide/SLM_Admin_Guide_Publish.pdf

Cisco的作業系統也叫IOS,不過和Apple的不同...
http://www.2mul.com/web/TW/products/ios/index.html

知道是什麼作業系統有何用呢

基本上 SG300 使用的是 CISCO 自己的 IOS (Internetwork Operating System)
但不支援少部份指令

以下為網路資料供參考

<pre class="c" name="code">
This is a very high quality switch, with extensive features. It runs running Cisco IOS that includes tons of advanced capabilities, such as QoS, port monitoring, and Layer3 switching (static routing). The whole Cisco SG300 line (but not the SG200) family now runs a bonafide version of Cisco's IOS software, making it compatible with the IOS Command Line Interface (CLI). (Be sure to check the Cisco site for the latest firmware). The IOS enhancement also completely revamped the GUI interface, which is excellent. Take care, however, to remember to save any configuration changes you make, whether by CLI or GUI. Unlike other low-cost managed switches, the SG300 does not save automatically save configuration changes (this is the behavior of Cisco's Catalyst line switches also, so Cisco is just being consistent).

若你能以 CLI 連上去的話
可以下個 sh ver
可以看得更清楚
如下

<pre class="c" name="code">
reyback# sh vers
Cisco Internetwork Operating System Software
IOS (tm) C2950 Software (C2950-I6Q4L2-M), Version 12.1(12c)EA1, RELEASE SOFTWARE (fc1)
Copyright (c) 1986-2002 by cisco Systems, Inc.
Compiled Sun 24-Nov-02 23:31 by antonino
Image text-base: 0x80010000, data-base: 0x80562000

ROM: Bootstrap program is CALHOUN boot loader

reyback uptime is 9 weeks, 1 day, 5 hours, 34 minutes
System returned to ROM by power-on
System image file is "flash:/c2950-i6q4l2-mz.121-12c.EA1.bin"

cisco WS-C2950-24 (RC32300) processor (revision H0) with 21002K bytes of memory.
Processor board ID FHK0712Y068
Last reset from system-reset
Running Standard Image
24 FastEthernet/IEEE 802.3 interface(s)

32K bytes of flash-simulated non-volatile configuration memory.
Base ethernet MAC Address: 00:0C:85:4A:84:80
Motherboard assembly number: 73-5781-11
Power supply part number: 34-0965-01
Motherboard serial number: FOC071115RX
Power supply serial number: PHI061104EV
Model revision number: H0
Motherboard revision number: A0
Model number: WS-C2950-24
System serial number: FHK0712Y068
Configuration register is 0xF 

我們公司也是sg300，我也遇到這個問題，用opmanager這個監控軟體，可以抓得到port的流量，但無法監控cpu跟ram的狀況，很麻煩。