The Sanathanic / Hindu system of measurement of time for a day
starts with a wink of the eye.
The wink makes us, the humans, differ from devas who do not wink.
(That is why they are known as 'Imaiyavar' in Tamil – those who don't wink)
That means there is no time for them.
Time is applicable for us in the created world.
18 winks = 1 kashtam
30 kashtam = 1 kala
30 kala = 1 vinadi
60 vinadi = 1 naazhigai / ghati = 24 minutes
2 naazhigai / ghati = 1 muhurtha
30 muhurtha = 1 day = 24 hours
or
60 naazhigai / ghati = 1 day.
Another way is to take 'truti' as the basic unit.
Truti is the time taken for a needle to prick a lotus leaf.
60 truti = 1 prana (1 inhale + 1 exhale = 1 prana)
6 pranas = 1 vinadi
60 vinadi = 1 naazhigai
(and the rest continues as before.)
Another way of calculation is like this.
1 day = 10 jaamam.
10 jaamam = 30 muhurthas = 60 ghatis.
1 jaamam = 3 muhurthas = 6 ghatis
1 jaamam = 6 x 24 = 144 minutes = 2 hours, 24 minutes.
The further division of time until the basic unit is like this.
1 ghati / naazhigai = 60 vinadi / vighati = 24 minutes
1 vinadi = 60 lipta
1 lipta = 60 viliptas
1 vilipta = 60 para
1 para = 60 tatapras.
So a day was divisible into
60 x 60 x 60 x 60 x 60 x 60 basal units of tatapara
according to Hindu system!!