In the context of ESP8266wifi.h ,i have done everything possible to get this library and the last error i got was could download index unsupported protocol and the the nio such file directory please help #9147
Originally posted by **DarioGHub** May 21, 2022
The letters 'ets' are used throughout the firmware, SDK and esp8266/Arduino code.
1) first letters in the boot message:
```
ets Jan 8 2013,rst cause:2, boot mode:(3,7)
```
2) numerous define and function identifiers. Just [search](https://github.com/esp8266/Arduino/search?q=ets) the esp8266/Arduino distribution.
```
#define os_delay_us ets_delay_us
ets_printf_P(const char *str, ...)
```
3) filenames:
```
#include "ets_sys.h"
```
Tried Google, but nothing, excepting online dictionaries with hundreds of possibilities.
Also scoured ~10 Espressif PDFs.
Is it an acronym for Espressif Tensilica System?
Pedantic perhaps, but I'd like to know. A reference would be over the top.
Discussed in https://github.com/esp8266/Arduino/discussions/8578