  The galactic micro-quasar source GRS 1915+105 has been observed with the
Indian X-ray Astronomy Experiment (IXAE) several times over a period extending
from 1996 to 2000. The source has been observed in different luminosity states
and exhibits a rich variety of random and regular X-ray variability over a wide
range of time scales. It also shows a unique variability characteristic namely
the occurrence of quasi-regular X-ray bursts with period ranging from 20 s to
about 100 s which have slow rise and fast decay. The X-ray spectrum of these
bursts is hardest near the end of decay. In the low-hard state and bright-soft
state with rapid variability, the source exhibits quasi-periodic oscillations
(QPOs) with variable frequency which is luminosity dependent. Regular X-ray
intensity dips have been detected coincident with the occurrence of a giant
radio outburst. The source made a transition from a low-state to a high-state
in 1999 in less than a day and from a soft-bright state to a hard-low state in
2000 in less than 100 minutes during the IXAE observations. Details of these
and other variability characteristics of the source are presented in this
paper.
