In this review we summarize results of our analysis of the observations of
solar eruptive flares made by the Ond\v{r}ejov radiospectrograph for more than
twenty years. We also present some Potsdam-Tremsdorf radio spectra from our
common studies. Considering a 3-dimensional model of eruptive flares together
with the results of our magnetohydrodynamic and particle-in-cell simulations we
show an importance of decimetric radio bursts for understanding of plasma
processes in eruptive flares. We present drifting pulsation structures as
signatures of plasmoids, an unusual zebra pattern in the very early flare
stage, narrowband dm-spikes as the bursts generated in the reconnection plasma
outflows, radio bursts indicating a merging of plasmoids, pair of decimetric
type III bursts indicating the electron beams propagating upwards and downwards
in the solar atmosphere from the acceleration site, and a special decimetric
type III burst formed probably around the plasmoid. We present unusual radio
bursts connected with the rising magnetic rope at the very beginning of
eruptive flares. Furthermore, based on the analysis of decimetric continua we
estimated the level of the plasma turbulence in a vicinity of the flare
termination shock. Interpretations of all these bursts are based on models and
time coincidences with observations in X-ray, UV and optical ranges; in most
cases an information about positions of these radio sources is missing. To show
an importance of positional information, we present a rare example of
observations, where the drifting pulsation structure was observed
simultaneously with the observations made by the EOVSA radiointerferometer. All
the presented bursts are then summarized in a new scheme of bursts and compared
with the schema commonly used.Comment: 20 pages, 12 figure