  Diversity of the X-ray observations of dwarf nova are still not fully
understood. I review the X-ray spectral characteristics of dwarf novae during
the quiescence in general explained by cooling flow models and the outburst
spectra that show hard X-ray emission dominantly with few sources that reveal
soft X-ray/EUV blackbody emission. The nature of aperiodic time variability of
brightness of dwarf novae shows band limited noise, which can be adequately
described in the framework of the model of propagating fluctuations. The
frequency of the break (1-6 mHz) indicates inner disk truncation of the
optically thick disk with a range of radii (3.0-10.0)$\times$10$^{9}$ cm. The
RXTE and optical (RTT150) data of SS Cyg in outburst and quiescence reveal that
the inner disk radius moves towards the white dwarf and receeds as the outburst
declines to quiescence. A preliminary analysis of SU UMa indicates a similar
behaviour. In addition, I find that the outburst spectra of WZ Sge shows two
component spectrum of only hard X-ray emission, one of which may be fitted with
a power law suggesting thermal Comptonization occuring in the system.
Cross-correlations between the simultaneous UV and X-ray light curves
(XMM-Newton) of five DNe in quiescence show time lags in the X-rays of 96-181
sec consistent with travel time of matter from a truncated inner disk to the
white dwarf surface. All this suggests that dwarf novae and other plausible
nonmagnetic systems have truncated accretion disks indicating that the disks
may be partially evaporated and the accretion may occur through hot (coronal)
flows in the disk.
